stocking your workspace

[nosaj]

Just wondering from the other repairer's out there what would be a good starting place for stocking common things.The only thing we have here is the RatShack everything else is mail order, when I order I generally order extras for stock, but not know what will ever be the next thing I will look at I'd like to have common values on hand. Make it easier on mail order too to have a bulk order vs a little here a little there.

mainly resistors ohmage, wattage
caps
diodes
pots
Or anything else that might be handy to have in stock as there isn't anything around Pensacola

Thanks,
Jason

[Enzo]

I rarely venture to the Radio Shack. if I need some common fuse I am out of, and I usually go there for a pair of patch cords when I need to replace the signal cables on a turntable. Oh, and the occasional little DC power jack.

STocking a shop is an organic acrtivity that never ends. If you work on everything and have no idea what will be in next week, then good luck. Are you setting up a commercial shop? Or experiementing in your basement all by yourself?

When I order, it is usually from a house like Mouser, Allied, Digikey, and sometimes Jameco. Then industry-specific places like Antique Electronics (tubesandmore.com) and their wholesale wing CEDist, Magic parts (wholesale only), New Sensor. And consumer electronics oriented places like MCM, B&D enterprises.

REsistor kits are OK, but you wind up with a lot of things like 33 ohm and 9.1k that will never be used. Look through a few tube amp schematics. See some common resistor values? 100k, 220k, 470k, 1.5k, 470 ohm 2W, 1000 ohm 5w, and some others. Look at pricing. What do 10 of the resistors cost? Now what do they cost by the hundred. Especially if the Shack is the competition, a resustor that is 15 cents can turn into a one and a half cent resistor in 100 lot. COnsidering the freight will be about the same regardles, I usually just get the 100 bag. I have invested in drawer bins, so each value has its own spot. So I got 100 100k resistors. I figure it is worht the peace of mind to invest a whole dollar in a part value. Half watters are fine with me, and since I run a commercial shop, I don;t mind stocking several sizes. SOme guys prefer using 1 watt resistors. Up to you. On circuit board, I would usually prefer to stick with the original instead of going larger, because of space and fit issues. SOlid state circuits tend not to be so predictable, most any vale resistor can crop up. In power amps, I keep a bunch of cement resistors, the rectanglular 5 and 10 watt things. Mostly 5w, and other than those 1k for EL34 screens, I keep a lot of fractional ohm ones - 0.22, 0.33, 0.47 ohm 5w. These are common in solid state power amps.

Diodes? The 1N400x series are all 1 amp rectifiers - basic diode. They start at something like 50v and up to the 1000 volt 1N4007. You can always use a higher voltage one than you need, so absolutely no reason to stock anything but the 1N4007. It will work just fine in place of a 200 volt version. The price difference between 1N4007, 1N4004, 1N4003 etc is minimal. Especially if you are buying a bag of 100.

Little "switching" diodes like the 1N4148 are VERY common, and cheap. 1N4148 covers most of them. Fender prefers the very similar 1N4448. I stock both, but I do indeed stick with the 1N448 in Fenders, because their channel switching circuits can be sensitive to small voltage variations. A bag of 1N4148 would be good to have.

Zener diodes, well we see a lot of half watt ones and 1 watt ones. A few 5 watt types. And then the experimenter guiys like big stud mounted ones for lowering B+. I run a repair shop, so I always have a drawer full of 15v 1N4744 1W zeners. Zeners can be less expensive than plain old rectifiers, oddly. Other zeners, well let experience direct you.

Clearly there are other common enough diodes, but those are the main ones. I keep bridges around, and I have a variety of fast recovery diodes and some Shottkys. I have a drawer of misc LEDs. I keep some of the square red ones Fender likes, what are they 5mm? 6mm? And just a collection of plain old round ones in red and green.

CAps, well what will you be servicing? Tubes? Always good to have some 22uf/500v axial caps, and maybe some 10uf too. SOlid state stuff uses a lot of different types. Hard to get too selective, I use 10,22, 47,100,220,470,1000, 2200, 3300, 4700 caps, mostly radials, and in 16, 25, 35, 50, 63, 100v. And that is just the small electrolytics.

Tube amps want higher voltage caps, so film caps are common couplers. .047uf, .033uf, .022uf, .01uf are common enough, I get the 630v type mostly.

I don;t even try to stock pots. If I were building things from scratch it might be different, but pots in commercial gear are all made to order for the OEM. The 50k pot in a Fender won;t fit into a Peavey, and vice versa. There are too many, I can;t keep up. I keep a few common Fender types on hand, otherwise I just roll with the punches.

Tubes? If you are going to offer repairs, you need to have a few tubes on hand. Certainly a quad of 6L6 and of EL34, and some EL84. A fistful of 12AX7s, maybe in a couple brands. A 12AT7 just in case, and if yo fix SVTs a coule 12AU7s. I go through darn few rectifier tubes, but a 5U4, 5Y3, 5AR4 should cover most needs. Those are the most common.

WHat elese? Fuses. I keep a good selection of fuses in both the 1-1/4" type and the smaller 20mm types, fast and slow blow.

Transistors. Oh there are so many. ICs? What are you going to do? I keep TDA7293s and LM3886s on hand, but they are specific to a few things I see a lot. SOlid state MArshalls will be wanting those 72293s. COmmon dual op amps, used to be 4558s, now more likely a 4580. Or even the venerable TL072. Cheap and often used. A few TL074 quad op amps would be good to have. Used to see teh DIP-14 ones in Peavey stuff a lot, now I see the SOIC versions in Behringer a lot. Other common ICs are the three leg voltage regulators, the 7812, 7815, and their negative brethren, and of course other voltages are out there. Little 5-lug power amps like the TDA2030/2040/2050 are used all over in small amps and "practice" amps.

I think I have a pretty good parts collection, especially for a small shop, but mine pales next to what someone like Frondelli has on hand. But no matter how many parts you keep, there will ALWAYS be ones you don;t have and will need. Ask John, he has to put parts on the order list every day. I know I do.

[nosaj]

Here's my plan I'm a fast learner. I give myself 10 years to aquire enough experience to be soley on my own. In the mean time The old time repairers out there are getting to be 70ish, I'm 38 now(late start got involved with computers now they just don't hold they allure of amplifiers.) My thought and what I have been doing is repairing broken practice amps (broken inputs, power transistors, speakers) and whatever else comes my way. I'm working with a music instruction place where the clientele is middle school to high school and some older players. I figure making contact with them and providing good service will work into word of mouth. I just want to part time this stuff and at this point in the 10 year stretch stuff is hard to come by. So whatever I can find I repair if it's not too far gone.

jason

[Enzo]

Jacks - where was my head - the most common broken part on an amp.

Practice amp, yes, what goes wrong with them? Broken jacks, blown TDA2040 (or whichever IC), blown speaker, busted control. The other stuff rarely fails, occasional op amp.

And I am still in my 60s, thank you.

So you need to be a generalist. ALthough, in my experience, the vast majority of school equipment is solid state. Just had a couple combos through here last night. A small PV and a Fender RUmble 100. PV needed its input jack resoldered. Fender neded a new input jack.

There have been several threads here about stocking and sourcing parts. In this section. Scan down the thread titles. We also discuss test gear.

[jrfrond]

I think I have a pretty good parts collection, especially for a small shop, but mine pales next to what someone like Frondelli has on hand. But no matter how many parts you keep, there will ALWAYS be ones you don;t have and will need. Ask John, he has to put parts on the order list every day. I know I do.

Yes, parts ordering and stock maintenance is almost a full-time job, no matter how expansive your stock is, so the best bet is to listen to what Enzo has said and start with those. As you progress, you can order extras and build it up little by little. Just to give you a little reality check, nearly a third of our total square footage is dedicated to parts stock and I still order every day, and that includes stock replenishment.

Storing it all is another issue, and there are ways to do this efficiently, but it will also require a computer with an inventory database to find the bin locations. We have three of these: Akro-Mils - Industrial & Commercial Products ...in our shop, amongst other storage drawers, shelves and racks, and it's a very handy, compact way to store lots of parts in a couple of square feet. We call the "parts rotisseries".

I touched on the subject of databases. I have to tell you that, once you get past having more than a few part numbers in stock and more than a an intake of a few units a week, it will make your life A LOT easier to have a system to track it all. Sure, you can do the old-fashioned way of hard copy. The advantage is that it never crashes. However, we DO have computers now and it will surely keep you from eventually pulling your hair out.

[Enzo]

Too late, only hair left is on my chin.

[km6xz]

If you set up a database to track and order parts be sure to structure it carefully. Each part has a whole sh..tload of part numbers depending on the source, OEM and brand's in-house stock number. Typing in any one of those numbers should give you the generic part number that you really stock.
Semiconductors are cheaper now than ever, and fewer main types are spec'ed for new designs when considering amps, but in digital music realm you are going to have to get the exact parts from the manufacturer quite often because they are probably a custom programmed gate array.
If starting out, identify a niche where you can compete and specialize so your parts, data and test gear can be oriented more towards that specialty. Trying to do all things for all people is terribly inefficient unless large enough to see plenty of each model. Having the part on hand makes you a profit, having to order a part ruins your work flow and you will be lucky to break even. Don't take in things where you have any doubt whether you can make the customer happy, in turn around time, price , effective use of bench time. It used to be that service info and schematics were the most time consuming to store and collect but many of the manufacturers put their tech info on CD/DVD so you do not need a dozen 4-5 draw file cabinets like 20 years ago.
Since you have such a long term plan, why not apply to be an apprentice to a master tech for a couple years. Better if you can work is several shops so you have a better range of procedures and tricks to copy if they work well. And by all means, study. The basics of electronics will serve you better than learning the tricks because being about to diagnosis from solid logical analysis will work more often than by habit or routine. If your really know the basics of electronics, deeply, you will likely be the only one in your part of the state doing MI repair who does and you will be able to work on anything you would like to.
Get good reliable test gear that has enough stability and precision to give repeatable readings. Gathering unambiguous data before making a diagnosis will save lots of time and allow you to charge a fair price. Bad techs almost always cost more, take longer and have less predictable results, mainly because they have not learned to diagnose well before attempting to repair things. It almost always costs the customer more. There are a lot more bad techs than good ones, so strive to create the most accurate diagnosis possible before hacking into anything. Good test gear is one of the keys. Used lab type gear is not expensive and there is no excuse for having to guess as to what a circuit is doing.
If you have 10,000 pots in stock, you will not have all you need so focus on a smaller category of gear to work on until you can afford to stock enough so most repairs can be done in one sitting, with out having to reassemble a unit and wait for parts, or waste hours on tracking down just one part for one repair.
Save a lot of time with a policy of having every customer demonstrate the problem. The description they give will seldom fit the actual symptoms. By seeing the problem, and how he created it, you are way ahead. It takes a very long time to prove an intermittent or functioning unit is not the problem. Most gear is hooked up to a lot of other gear so ask how they determined the piece they brought in was the suspected defective unit. Quite often the unit they bring was picked because it was the lightest or easiest to unhook. Trying to get a working unit to fail, solely by the customers assumption that this one unit was the cause is a recipe for lost productivity. If you see a problem occur you can fix it, the ones that do not fail on the bench are the major time wasters, which you can't charge for. By learning to ask the right questions you can cut the number of "No Problems Found---No Charge" down to almost none. If you are talking to the client directly, the incoming interview can frequently get you half way to the final diagnosis.
Good luck...

[nosaj]

You mention quality tools, what would you recommend. I have a decent DMM, Tenma 20mhz with function generator, isolation transformer, dim bulb tester and hand tools, and the internet. A small library of books ranging from 50's to present. At this time apprentice ship is unlikely as nearest shop is 30 miles away and my daytime job is network administration which 99% done from home so I have to be avail daytime but I can piddle at home. I would love to apprentice but at his point it doesn't seem to be in the cards, so I've made friends with the local hams and pick their brains when I can. None of them really fool with tubes anymore but they still have the knowledge, toys and sometimes parts buried in their shacks.

So I've taken every amp I come across thrift store, craigslist, friends, etc and fix what I can. So far everything has been reasonable on return. On computer's I used to 1-2 turnaround, the amps about the same plus parts shipping.

I just see a market for this in about 10 years if not soon, as the older people will most likely retire or nature happens and I want to be there to fill the gap. When I started working in computers no one in this area really did it and now it's like shade tree mechanics around here. We live comfortably being self employed but I've always been of the mindset the more I know the less likely I am to starve. And if something like The Stand ever happens I want to be able to make stuff go instead of relying on someone else but that's just me I hate paying someone for something I know I can learn.

but enough rambling.


Thanks for everyone's opinions and advice

jason

[km6xz]

Hi Jason
I wrote a long email to another member yesterday on this same subject of test instruments...it has to go email because it was 22,000 characters over the limit;>)
I'll send a copy to you....
Stan

[g1]

Save a lot of time with a policy of having every customer demonstrate the problem. The description they give will seldom fit the actual symptoms. By seeing the problem, and how he created it, you are way ahead.

If you see a problem occur you can fix it, the ones that do not fail on the bench are the major time wasters, which you can't charge for. By learning to ask the right questions you can cut the number of "No Problems Found---No Charge"

Agree completely with the first statement, completely disagree with the second
Establish a bench minumum, post it, and stick to it! One of the shops I worked in had the "no problem no charge policy" and we became the free testing facility for the entire area, as all the other shops had strict minimums. Testing is bench time, so is estimating. Most guys will only charge for refused estimates, approved estimates are part of the labour time. Remember finding the problem is usually the bulk of the repair.
Another point I will make while we're a bit off topic: the bulk of repairs is broken controls, jacks, and solder connections. Not much knowledge required to do the bulk of the repairs, it's that last 20% (or whatever the number) that requires electronics knowledge and troubleshooting skills. This small percentage of repairs is what separates the wheat from the chaff as far as technicians go.
One of the best things I was told by one of my college electronics teachers "do you want to be challenged or make lots of money?". The simple repetitive jobs are the money makers, the challenging ones are often "break even", until you've done them often enough that they are no longer challenging.

[jrfrond]

Fee structures for the repair shop are a whole 'nother ball game. No matter what methods you employ, it must be in the shop's favor. Two things prevail: you must get paid for time and you must NOT become a storage/repository facility. We charge the estimate fee up front on ALL non-warranty items, and we also charge storage fees past 30 days of notification of completion, unless the customer has informed us that they will be delaying pickup. We also make use of disposal notices via certified mail past 60 days, at which point, the gear is sold off if we aren't compensated for the repair. "G-one" is correct: you MUST establish a system and stick with it, and don't bargain or word will get around that you can be "had" or "worked", and in the long-run, it doesn't look very professional. Some customers might not like the hardball approach, but that IS the professional way. I hate to mention it yet AGAIN, but this is ANOTHER reason why you need a good database system, because unless you can track units in a timely fashion when the customers call, you run the risk of looking unprofessional. Now, it might be a regional thing, I don't know. Perhaps I am hyper-aware of this because we are dead-center NYC, and you must be on your game, or you wind up receiving bad press via word of mouth or the internet. I think that the major urban areas might have to be on top of their image, whereas other areas might be more laid back.

[km6xz]

There are many ways to bill, charge and estimate, it is one of the individual characteristics which defines a shop in the minds of customers.
To fit my own business model and personality, I never charged for estimates or no problem found. If we gave a reasonable estimate, they were seldom turned down so it was not a risk for us to spend some time with the clients equipment, so it was only to our benefit in creating a positive image for the customer, the results were the same. If there were two shops, one with free esitmates and another with a minimum and upfront estimate fee, a not so small portion of potential first time customers would pick the one that required the lesser of commitment, without realizing they WERE going to have it repaired regardless of what they were hoping for, unless the counter girl found the problem and it was easily corrected at the counter for no charge.
We did not charge for no-problems found because we tried to focus the checkin process on pinpointing the problem. The girls at the counter will likely better informed on drawing information from customers, and guiding them through dupelicating the problem before it was even checked in. There was a side table with an array of signal sources, current limited supplies, breakers and variac, plus a active electronic 3kw load. The monitor speakers were not connected to the unit, they were driven by a small amp which had a hi-Z sampling of the load, so with or without load the sound coule be heard. It was all very neat and not at all like a tech bench, the gear was below in the cabinet. The girls were the first line of diagnosis and were able to get musicians and DJs to define the problem even if they were not terribly articulate about tech stuff. That first interaction with the shop that did not look like typical shops at all was intended to leave a positive impression without damands to talk to a tech. The girls were cute, friendly and usually knew more types of gear and how to define problems than 95% musicians or home studio engineers. Estimates were pretty accurate just from going to the database, typing in the model a list of prior repairs for the same symptoms, a average cost and range of costs would appear. After averaging 500 repairs of the same model, there are not too many surprises.
The custmer experience was important to me and helped speed our growth. The initial 5,000sq ft shop was added onto with a 5,000sq foot warehouse with shipping dock and forklift, and eventually we added a second floor to 1/2 the warehouse and the offices so we ended up with 13,000 sq feet of shop, all R&D type modern facility, with thick quality carpet in all but the mail warehouse floor. The lobby was bigger than the other shops in total which I knew in the region, with 16 ft ceiling and all glass front, nice furniture and the two most commented-on features, #1; the pretty counter girls/ manager who really created smiles, particularly....#2 when they brought out the signature super special fudge brownies that were the customer snack. We had a full kitchen added so a couple times a week someone would cook another batch of the brownies. In season we had fruit, and ice tea availavble, hot tea in the cooler months although the entire facility was air conditioned.

The image perceived at all turns was considered and designed to separate us from the competition. After a 18 months we really did not have competition.
Thursday nights were used for workshops and lectures by reps or tech seminars. About once a quarter there was a tech night of people could bring in anything and we would give it a quick run through..power out, distortion, noise, freq response in sort of a short lecture of what it all meant, comparing units design and sound for studio gear, guitar amps etc. A dozen or so amps would show up, sometimes new ones where the new owner wanted to show off or a broken on hoping to learn what was wrong. It was a fun evening often and it attracted a lot of new clients. If a very minor problem was encountered I would try to fix it as part of the demo, all free. I patterned that after the old MacIntosh Clinics where distortion, power and frequency response was measured and graphed by hand, and if the unit was a MacIntosh and did not meet spec, it got new tubes or whatever to bring it up to spec for free. Those were famous from the 50s to early 70s. One engineer's full time job was traveling around the country giving this clinics in stores which carried the brand. I was really impressed with the strong impression it created in a lot of non-Mac owners, like me at the time. I did the same sort of thing in a number of regional stores at the request of store managers or factory reps. Those were usually more limitied in scope, One only for ADATs one time and only guitar amps another.

We lived in one of the most expensive regions of the world and I doubt now there are many homes selling for less than $1,000,000 but few people were really free spending. Despire the cost of living we never really got above $65 an hour until about 2000 when it went up to $75 when the other shops were charging $80-120. Basically no one charges by the clock but rather what it ought to cost. A rework of an ADAT, very big at the time, or DA-88 generally was $90. Alesis was charging $275-325 and shipping them to us by the pallet load.
We made good income on the reasonable rates because there was a significant effort expended to make things efficient. Such as the confirmed fault before a unit was ever checked in. Having the most used parts in stock saved a lot of time and reassebly if it needed to be shelved waiting for parts. Having fully equipped benches, usually two per tech where two projects could be done at once, say one could be left open on 1 bench while the customer was being notified or a next-day part was going to arrive and another active diagnosis occuring on another bench. Having large volume of the same models really helped. I have always been a test gear hound so anything needed for any sort of repair from 10 millihertz to 10 gigahertz could be generated, measured and analyzed with ease. Most equipment was Tektronix, HP/Aligent, and Sound Technology some Motorola or IFR for RF thrown in. When companies wanted equipment lists to see if we were qualified to serive their gear, they would get a 10 page close spaced list of good lab type gear. There are lots of not too expensive way to increase efficiency, in fact double the income without raising prices. Doing away with paperwork helped a lot.
The idea of selling off customer units needs to run by a lawyer who deals with the consumer protection laws in your state. We never sold anything nor threatened to, it was a policy not to. What we did to keep finished unit storage down was to complete units quickly. The long a repair took, for whatever reason the changes of the user getting used to the spare and forgetting about the one in the shop increases. Keeping repairs down to 2-3 days if parts did not have to be ordered kept the storage area turning over. A law suit over improperly disposed of gear can ruin a small business understand the law as the courts interpret it, not how other businesses are getting away with.

That was just my way of doing it, there are as many different ways as there are shop owners. In a small town without competition, a different policy would probably be good.
But each shop has to create its own niche or else the competition will control your place im the market. Answering the question "with 15 words, why is my shop the one place the customer should bring their gear", if there is no clear answer or "because I am good" than there is a problem and whims of competitors will take market share at will and they only leave you alone because they do not have a clue either and are also drifting.
Every area has unique opportunities and challenges, the winners are the ones who identify what those are and build their business around them.

[nosaj]

Not to be rude or anything but your post implies past tense. Why do you no longer have this business?

Thanks,
Jason

[km6xz]

Not rude at all, I used to have this shop until I decided on a spur of the moment to give everything away and move to another country......in 2 weeks. As fate would have it, it took 3 weeks to give my things away including both locations to the employees. They ran it for another year and then sold off all the assets, test gear etc. and went away. There were a lot of squabbles apparently, and no clear direction. Two dozen chiefs does not work out. That was 2004. One key reason for them disolving it is that they could not get the work done at the same level without me there. With 15 techs a good chunk of the diagnostics and repair income was from my own hands, I was a workaholic and had two repairs going at once and would still have time to walk around helping each bench diagnosis. After being totally out of pro audio since 2004, I had the urge to smell the solder fumes again. I set up a pretty good bench in my apartment in St Petersburg and repair things for clubs, theaters, and musicians I know just for fun...last night with a sparking and burning SVT, a Moog Theramin earlier in the day and built a digital RCLz analyzer in the morning.
I have gotten into importing tubes because there is a need, and working on my own brand. My project for now is to develop a service network, a first for Russia, where competent repairs in major cities can be done and have a central database, service records db and imported parts which are not available at all her. There are very few shops, less than a dozen in a country of 145,000,000 because there are no parts available from the 2 distributors of all things MI or pro audio.
So I am in semi-retirement, having a ball in a beautiful city full of beautiful women and had not even thought about repairs for several years until the bug hit me a few months ago. If I ever move back to the States it will be in a distant rural place in the mountains or along the western sea coast, and see what sort of small business needs to be done, There might be some real interest in the new tubes being worked on, and my way of testing and matching which is pretty cool and much more informative than what now passes as matching or specs. That is something that could be done if not too far from a post office or rail line.
This is my 3rd retirement and this has lasted much longer than the others. The previous one was from the recording industry. Freedom and calm lasted for almost a year and then I opened a small one man field tech operation out of a back porch for repairing and calibrating studio gear. That sort of took unexpected leaps in other directions.....ended up with a real shop with my GF and hired second tech. That small 500 sq foot shop was outgrown in a year and leased the big shop and expended it regularly. That was 1992-3ish when the one man operation started. 18 months later we were in 5,000 sq feet and another 18 months added the warehouse and hired the 12th tech. I always traveled a lot and on one of my frequent trips back from Russia I decided that my happiness was there and not in California, I would get depressed every time over the last few days before departing to return "home". I decided on the plane that I would dump everything but one house, one car, some test gear and awards, books and photos. 3 weeks later I was standing on Nevsky prospect with 2 large suit cases with no idea of where to live, how to earn a living, how to speak much of the language....and smiled, I like challenges and living creatively. It has been great, not once regretted the rash stunt. I have met more good friends than I have ever had, have had more time to explore things that matter more than big houses and fast cars.

[drewl]

I'm a pack rat, so I have parts out the wazoo....
You see some cheapo little amps at a garage sale for $5 or $10?
Pick em up, they'll be loaded with parts you can use. people usually give me those things, so I have like a half dozen little practice amps around.

I work with electronics in my real job, so I get tons of parts from stuff being scrapped out.
You see someone throwing away a computer or vaccum cleaner?
There's power cords (provided they're 3 prong) that can be used, especially for converting old amps to 3 prong.

And when you order stuff from somewhere, there's always a discount for quantity, so order ten of something like pots or jacks etc. because you will use them.