Just not my night, I guess

[Enzo]

Crap.

Got a package from TEAC today, supposed to be the MIDI/USB board for a US-1800, yay. In the box is the analog I/O board instead. Gotta send that back.

Next, a Roland JV-30 with tiny little output. Hopped right inside that, found low signal everywhere, got suspicious readings on some of the mutes. FOund the service manual online and got that. Wasted an hour, and finally thought to meself, "Uh geez, I haven;t reinitialized this yet, have I?" Press a couple of buttons and say YES, et voila, sounds great.

Oh well, the Crate amp should be easy enough. GT100H. Hmm, don't have that. Went to the Loud site for the schematic, didn't see it. Wasted more time until I realized, oh yeah, the GT100 is on the same schematic as the GT50. Sure enough. No through signal. Traced it to a bad op amp. Big board to come out, disassemble just everything. Installed a nice new TL072 IC, even did real nice solder work. Put it all back together, no work. Sure enough I had professionally installed the IC backwards.


I'm gonna have me a bowl of Cheerios and take a nap. Tomorrow is bound to be a better day.

[DrGonz78]

Maybe Lucky Charms might help more? Back in the day I would just wake up and toke a few bowls to get my day started out right! If I did that now I would just crawl back into bed and pass right out again.

[Dave H]

Installed a nice new TL072 IC, even did real nice solder work. Put it all back together, no work. Sure enough I had professionally installed the IC backwards.

I once professionally layed out all the ICs on a PCB mirror image by counting the legs in the wrong direction. It worked better when I re-installed them from the solder side.

[Mark Hammer]

I have those nights. And sometimes they turned into weeks.

Luckily, they would be occasionally interspersed with weekends where I could do no wrong.

[olddawg]

Seems that things have not changed in the repair universe. One of the reasons I left the field was there were so many board revisions and production runs on anything incorporating anything digital that it was frustratingly tedious to repair most things. Of course I was doing mostly video stuff. Firmware upgrades EPROM re-writes as well. Call technical assistance.....they are clueless. They send you a board. The board is incompatible. Then you put it in a box and ship it to them. They replace the unit with a different model.... And on an on on on an on. Lol.

[52 Bill]

Boy, I'm glad that I'm not that professional at this stuff. I've never had a day like that.

[pdf64]

I spent a few evenings last week puzzling over a buddy's FBT powered PA speaker, which had been cutting out.
After fixing a volume pot that had become detached from the pcb, there was still a lot of noise, turned out that the pot track was bad.
Replaced that and it was a whole lot better, EXCEPT that at very low levels it cut in and out.
Spent hours trying to track down the dry joint / bad connection / over sensitive protection circuit that was causing it.
Eventually it struck me that there may be a noise gate lurking somewhere in there, that was not referred to in any of the documentation. The manufacturer confirmed that was the case, I'd wasted a lot of time trying to fix a non-existent fault - doh.
Pete

[Gtr_tech]

Crap.


Oh well, the Crate amp should be easy enough. GT100H. Hmm, don't have that. Went to the Loud site for the schematic, didn't see it. Wasted more time until I realized, oh yeah, the GT100 is on the same schematic as the GT50. Sure enough. No through signal. Traced it to a bad op amp. Big board to come out, disassemble just everything. Installed a nice new TL072 IC, even did real nice solder work. Put it all back together, no work. Sure enough I had professionally installed the IC backwards.


I'm gonna have me a bowl of Cheerios and take a nap. Tomorrow is bound to be a better day.

Just another reason to install a socket first....'specially on those all on a single board jobbers.

[Enzo]

I almost did, but I thought, "Nah, it will just be a source of intermittants later." Oh well...

[DrGonz78]

Sold a guy an amp one night and talked to him about wanting to get to the point of repairing other peoples amps. He had a guy that he would bring his amps to for various repairs. Three days later he calls me up and asks for my help on a Blue Voodoo combo amp. Apparently, he was trying to do some basic soldering but it was not going very well. An hour later he is at my house with the amp. He and his teenage son were trying to get to the amp's insides but were not unplugging it from the reverb tank. So I take the thing apart and start doing the soldering that was required. Very basic expansion PCB on the top did not require removing of the entire board. Even then you needed to pull out the tubes to set the chassis flat on my bench, but apparently they never removed the tubes. He also wanted me to solder the input jack in better so then I had to pull the board too. Hit a few extra solder joints for good measure while I was in the beast.

Anyhow, got the whole thing put back together and turned it on... Pushed the standby switch to find no signal output on the amp. So called him up to let him know and he was just so calming saying "don't worry you'll figure it out I am confident." Problem was this is my first "client" for any repair of amps that I did not own. At this point my inexperience of guitar amp repairs hit me like a brick wall. My thinking got cloudy at first and dived into the amp like some rabid fiend on a mission from God!

So I took the whole thing apart again to make sure the board was not intermittent. I was a bit overwhelmed and confused. The board looked like it could benefit from solder re-flow, so I did the whole board to make sure. Spent about an hour doing that and then put the amp back together. Putting in each tube and on the last 12ax7 I notice finally a frosted bulb. Also, the tip of the tube was nicked off and it all became clear what had happened. I knew I did not chip the tube, and imagined it happened when his kid and him working on the amp in a precarious manner. I had a good preamp tube on hand and it fixed the problem. There was also another 12ax7 that had the tip nicked off but it was still working. So, somewhere between pulling out the tubes and putting them back in... the tube went frosted flaky!

Luckily I have a ECC81 laying around and figured it would help me at least get the bastard up and running. Plugged it in and got the amp all assembled. The amp rocked!! Went from "Just not my night" to "Thank the amp gods... Boy did I get lucky night!!" At that point I had been working on amps for only about 3 months tops. I was in over my head but luck prevailed. Since then I have fixed a few different things for this client and become good friends. Most recently it was repairing some M-Audio BX5 monitors.

It's so strange how you can be just rolling right along fixing this and then fixing that and then WHAM!! A total stream of bad luck hits. I hate that feeling and the best remedy thus far has been some good strong IPA's.

Edit: BTW I will never ever ever work on a modern GK BL210 BL600 or anything with those evil PCB boards ever again. Every night I tried to fix that BL210 it kicked my ass to the curb!! Also, my rule of thumb this last year buying amps is to turn down any amp that has surface mount technology. Turned down countless offers to buy Line6 and Behringer products. Sure fixing cheap chinese amps is one thing, but I only take on the one that have barely any SMD. Like occasionally a Fender with DSP or something but the rest of the amp has normal looking components on the PCB.

[soundguruman]

"BTW I will never ever ever work on a modern GK BL210 BL600 or anything with those evil PCB boards ever again."

Burning Sage drives away evil...
However sometimes I gotta call a Medicine Man, for the real tough stuff.

[Enzo]

Never ever ever is a real long time. And times do change, you know?

[Jazz P Bass]

[QUOTE=soundguruman;286843]"BTW I will never ever ever work on a modern GK BL210 BL600 or anything with those evil PCB boards ever again."

QUOTE]
Gotta agree with you there.
What a lousy PCB layout.
Thin traces, too small pads, way too many vias.....
Whoever laid out that PCB was either stoned, inexperienced or had a real hardcore bean counter on his ass.
I will work on them though

[DrGonz78]

I guess if someone brought one to me I would still want to try to work on fixing the amp. I was way more inexperienced when I was working on this amp and that taught me something for the next time. I know better how to work on this amp, but it was still a nightmare. So yeah it is like a fear or phobia and still I guess I would subject myself to that torture!! Kinda like when I was in plays acting... I hated it but yet I kept auditioning and getting parts. So yeah never ever might be my hope but yeah when push comes to shove... I am gonna shove right back!!

Whoever laid out that PCB was either stoned, inexperienced or had a real hardcore bean counter on his ass.
I will work on them though

I am voting on that one!!!

[J M Fahey]

Thin traces, too small pads, way too many vias.....

Well, I vote on the inexperienced designer.
These 3 characteristics are typical of the "default" setting in most PCB packages.
No, they don't make the process any cheaper , but they make it easier for the auto router.
Thin tracks and small pads allow for "more free space" ... literally; and vias all over the place mean on any difficulty, the track simply switches to the other side, and placesw a via to join both sides.
Being made out of electrodeposited lead, vias are a poor imitation of a real connection.
A sensible trick is to place 3 vias in a cluster whenever tracks switch sides ... but not many do this.