old 'scope for home tube amp work

[mikepukmel]

Hi All,
I have done some reading, and some of the blogs have lists of scopes they suggest for newbies and scopes to stay away from. Several of the lists have Tektronix 475 on the 'good' list. Anyone have any strong feelings one way or another?
There is one for sale locally, so no shipping, $150.00 with a cart. (Its a frickin tank, you could park a car on it) Ad says it works. If these break down, how expensive is it to get one fixed? Can they still get parts? One of the blogs said these models were better since they didn't have lots of exotic custom parts, more off the shelf type stuff.
Very anxious to see what these waveforms look like as they propagate through the amp!
Thanks,
Mike

[J M Fahey]

I suggest you offer $50 and wait a couple Months until he realizes yours is the best (and only) offer and he HAS to clear that garage/basement/attic NOW.

Repairable? maybe ... and probably Military/Universities HAVE to repair their own spending a few thousand while a better modern scope costs a few hundred, but then they need authorization from the red tape Gods; in your case failure means junking, there´s no other practical option, so test it well before paying.

Or plain buy a cheap modern one.

[mikepukmel]

I suggest you offer $50 and wait a couple Months until he realizes yours is the best (and only) offer and he HAS to clear that garage/basement/attic NOW.

Repairable? maybe ... and probably Military/Universities HAVE to repair their own spending a few thousand while a better modern scope costs a few hundred, but then they need authorization from the red tape Gods; in your case failure means junking, there´s no other practical option, so test it well before paying.

Or plain buy a cheap modern one.

Thanks, Juan. I do get the feeling, by the ad, that they are doing just that: got an order to "Clear out that basement now!" The stuff doesn't look really beat up, but its ancient. Hate to get something that doesn't work and it takes me a few months learning to figure that out.

Any suggestions on brands/models to look for? Ive seen a bunch of Youtube 'how to' videos that use Rigol scopes. Really small, look modern. I hope to stay under 500.00 usd, which is not much for a tool like this.

[Tom Phillips]

...Tektronix 475 ... for sale locally ... Its a frickin tank, you could park a car on it...

Mike,
Based on that description I'm wondering if the model number isn't a typo.
The attached photo is a Tek 475. Does it match the model you are considering?
Tom

[mikepukmel]

Mike,
Based on that description I'm wondering if the model number isn't a typo.
The attached photo is a Tek 475. Does it match the model you are considering?
Tom
[ATTACH=CONFIG]44452[/ATTACH]

Oops, its actually a 475A. But, yes it looks like that, more or less. The section on the right half looks like it, the left side looks different.



It comes with a stand and a tek multimeter. I think that's why its a little pricier than the other scopes around its vintage?

[mikepukmel]

Just got a note back from Tektronix. They didn't laugh at me via email, but I think they were laughing when they wrote the email.
Basically "fugedaboudit". no parts, no repairs, no service, no support.

They do calibrate them, though, which is nice.

[mikepukmel]

The hunt continues...

[Tom Phillips]

I use the 465 series scopes. Both the 465 and 475 series are good scopes. However, they can be a hand full to maintain. Worth it if you have the time and experience but maintaining them is not for the fainthearted. There are good support groups on the internet. Certified calibration would cost $300 to $400 or more but my scopes never needed it for amp work.

[Mick Bailey]

With older Tektronix scopes it's wise to check every function works correctly before buying. If you can't do this I would avoid paying very much at all. The mechanical components don't have too many problems. However, the electronics side can have issues; power supplies sometimes need capacitors replacing, and there can be serious image burn on the screen. Some hard to find components are the tunnel diodes, as well as some calibrated transistor pairs that are also tricky to match up if one fails. There's a high-voltage section referred to as the 'DC Restorer' that uses unusual capacitors and pretty much the only way to get these are 'pulls' from a donor scope. I wouldn't be without my 465 though. You get really used to a particular scope and this one fits me like an old pair of shoes.

Tektronix has a superb scope troubleshooting guide that's worth downloading. The philosophy it outlines for fault-finding is good for many types of equipment besides scopes.

[nsubulysses]

I got two Tektronix 465s for $100 each. One on craigslist one on ebay.

I have a Tektronix 453 and a Tektronix 2235 (sold it for $100 on ebay) that I got for $30 each on craigslist. The good deals are out there for the $30-100 oscilloscope if you can come across them.

Not to undercut Tom Phillips who is always a good source for information but theres a better deal out there for certified calibration

I got this quote from a Tektronix location in Addison, IL, not far from where I am. I never ended up dropping them off for cal. I just got a new Rigol digital scope for comparison against my old 60s, 70s, 80s Tektronix and they were in cal or very close. A slight nudge of the trimpot and they read the same as the new Rigol. Be careful, CRTs are usually 3000-7000V DC or so



Edit: wow I can't belive the quote is from early 2015. Time flies. Maybe it's more expensive now.

[mikepukmel]

I use the 465 series scopes. Both the 465 and 475 series are good scopes. However, they can be a hand full to maintain. Worth it if you have the time and experience but maintaining them is not for the fainthearted. There are good support groups on the internet. Certified calibration would cost $300 to $400 or more but my scopes never needed it for amp work.

I'm a 99 pound electronics weakling, so I don't see myself diagnosing or fixing one of those modules.

[mikepukmel]

With older Tektronix scopes it's wise to check every function works correctly before buying. If you can't do this I would avoid paying very much at all. The mechanical components don't have too many problems. However, the electronics side can have issues; power supplies sometimes need capacitors replacing, and there can be serious image burn on the screen. Some hard to find components are the tunnel diodes, as well as some calibrated transistor pairs that are also tricky to match up if one fails. There's a high-voltage section referred to as the 'DC Restorer' that uses unusual capacitors and pretty much the only way to get these are 'pulls' from a donor scope. I wouldn't be without my 465 though. You get really used to a particular scope and this one fits me like an old pair of shoes.

Tektronix has a superb scope troubleshooting guide that's worth downloading. The philosophy it outlines for fault-finding is good for many types of equipment besides scopes.

Thanks Mick. The units are only about 40 minutes from my house, maybe the seller will give a demo to see if everything works.

[mikepukmel]

I got two Tektronix 465s for $100 each. One on craigslist one on ebay.

I have a Tektronix 453 and a Tektronix 2235 (sold it for $100 on ebay) that I got for $30 each on craigslist. The good deals are out there for the $30-100 oscilloscope if you can come across them.

Not to undercut Tom Phillips who is always a good source for information but theres a better deal out there for certified calibration

I got this quote from a Tektronix location in Addison, IL, not far from where I am. I never ended up dropping them off for cal. I just got a new Rigol digital scope for comparison against my old 60s, 70s, 80s Tektronix and they were in cal or very close. A slight nudge of the trimpot and they read the same as the new Rigol. Be careful, CRTs are usually 3000-7000V DC or so

[ATTACH=CONFIG]44459[/ATTACH]

Edit: wow I can't belive the quote is from early 2015. Time flies. Maybe it's more expensive now.

Thanks for the info. maybe I'll keep looking, or at least go and see what this one looks like, if its really beat up or not. The photos in the ad aren't very good.

How do you like the Rigol? Ive seen some lower end used units for fairly cheap on Ebay and Craigslist.

[bob p]

Be forewarned that Tek scopes from that era often use proprietary parts. that limits your repair options.

I would not worry all that much about certified calibration for amp work. I say this as the owner of a rack mounted HP oscilloscope calibration unit.

I've always found decent test gear at decent prices on ebay. My first scope was a Hitachi/BK dual channel scope that I got for $50 on ebay. Still working, it's been a workhorse for me. I also bought HP signal generators and frequency counters for next to nothing. I got my HP distortion analyzer the same way. On a lark I bought a working vacuum-tube Heath O-10 oscilloscope from an auto mechanic on ebay for 99-cents.

Hamfests are the ultimate place to shop for these types of things.

HACKADAY: Old Test Gear and Why It's Awesome

[mikepukmel]

Be forewarned that Tek scopes from that era often use proprietary parts. that limits your repair options.

I would not worry all that much about certified calibration for amp work. I say this as the owner of a rack mounted HP oscilloscope calibration unit.

It's pretty easy to find decent test gear at decent prices on ebay. My first scope was a Hitachi/BK dual channel scope that I got for $50 on ebay. Still working, it's been a workhorse for me. I also bought HP signal generators and frequency counters for next to nothing. I got my HP distortion analyzer the same way. On a lark I bought a working vacuum-tube Heath O-10 oscilloscope from an auto mechanic on ebay for 99-cents.

Hamfests are the ultimate place to shop for these types of things.

HACKADAY: Old Test Gear and Why It's Awesome

Thanks! There was a long blog post someplace, from a tech who wrote out a couple of lists of old scopes, and this was one in the list he said had fewer hard to find repair parts. But, that with a grain of salt, who knows how much repair work he actually did.