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#62
Hoochie Coochie Man said:
I see the circuit board is a through-hole design. One advantage of surface-mount technology, is that, (depending on the orientation of the board to gravity), the components that get real hot will unsolder themselves, and just fall off the board. That's why I always run my PF-500 upside-down. Just in case. Ya know?
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I have actually seen that happen. We had a software test engineer go home for the weekend, while leaving a VHF transceiver he was testing in transmit. Some components slid right off the pads, shut it down.
 
#63
All you need is a 1/4" cable and just pop it in and out if the effects loop jacks a few times. That thing will be up and running in no time.
 
#68
BurningSkies said:
Is this one of those amps they say you can hose down to clean them out...as long as you let them dry thoroughly before testing? Maybe that's an option.
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Actually an electronics teacher I had recently sprayed some kind of purple spray cleaner from the dollar store right into a 50s Gates compressor and then proceeded to hose it down. It worked great. I wish I had made a video of it.
 
#69
two fingers said:
Actually an electronics teacher I had recently sprayed some kind of purple spray cleaner from the dollar store right into a 50s Gates compressor and then proceeded to hose it down. It worked great. I wish I had made a video of it.
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I know a couple of guys who have done similarly with amps. If you do a search on TB you'll find some posts.
 
#70
danosix said:
Actually, 50 is 10% over 45.
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Obviously (and it's really a hair over 11%). That was my point, that 10% is the absolute minimum. Most references recommend a bit more than that for a robust design. Choices are limited because capacitors (for the most part) come in a relatively small number of standard voltages, and the next voltage up could be a significant jump (63 in this case, which is not overkill). It all comes down to balancing price, performance and, to an extent, space (higher voltage caps are generally larger).
 
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#72
two fingers said:
Actually an electronics teacher I had recently sprayed some kind of purple spray cleaner from the dollar store right into a 50s Gates compressor and then proceeded to hose it down. It worked great. I wish I had made a video of it.
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Surprisingly, it's not uncommon to clean electronics with water-based cleaners such as Simple Green and then rinse. I don't (I usually use alcohol-based cleaners), but people do it. The important things are to dry thoroughly with compressed air right away, and don't spray things that can trap water inside, like pots and transformers.

BioWeapon said:
It seems I'm not as informed as I had thought :D
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Hey, I'm not either, and I'm not always as nice as you are about admitting it!

It seemed more logical for me to think that the circuit could be designed to use any voltage, and that circuit topology and design along with current would determine output impedance and power. Hence why some amps run on 40v, 250v, or 12v (eg solid state, tube, and car-specific amps). But then, I have no formal education where circuitry is involved. Eventually I will, but not yet!
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The mains, or power input, voltage is either wall voltage (which varies by country) or 12V for car systems, but that gets stepped up or down in the amp's power supply to whatever working voltage the amp needs to make its rated power. These caps come after that.

Reid
 
#74
Nev375 said:
My electronics teacher had a similar saying. Troubleshooting is easy, It's usually just a fuse or something else.

He's exactly right and this one fits in that "something else" category.
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Goes along with "it was working before..." Things always work until just before they don't!
 
#76
ReidK said:
First, let me make it clear that I'm not blaming the caps for what happened here. It doesn't look like they blew.



OK, I'm just a little surprised to hear that (though I'm not surprised that you might prefer 63V caps - if you were going to put your name on this amp, would that "might" become more definite?). I've always read that 10% over nominal operating voltage was an absolute minimum, and I'd expect GK to do more than that. Most higher-end amps that I've seen have more like 20-25% headroom in the voltage spec for the first stage filter caps, some have more.

Of course there are a lot of those amps still working fine. I didn't say it was too low, I said "cutting it close", which I still think it is.

Reid
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I'll take aged horse's opinion here blindly since I play a Genz Benz el Diablo guitar amp ;-)

Best amp for.... Well, everything guitar related
 
#78
A couple of replies:

One of my lines at the counter is that every piece of gear, no matter the expense, nor its reputation for quality or lack thereof is just a 4 cent resistor away from becoming a slag heap.

We once swapped out an internal fuse on some device and charged the guy $40 dollars. He went a little livid. Of course this was after he approved an estimate for $40. He railed at me, "How can you charge $40 to change a fuse?" I explained that he paid $40 for us to check it in, the tech to tear it down, assess it, and then for him to get a phone call to approve the estimate, fix it, service the jacks and pots, put it back together, test it, write it up and give him another phone call that it was ready. The tech hears this, comes out and says in his best grouchy tech voice, "Changing the fuse was $5.00. The other 35 was for having a guy with enough experience and knowledge to know it just needed a fuse to the point that you got a 90 day promise that it was just a fuse to go with it."

We had a Tremolux on the bench once a long time ago where you could make a little flame come out of one of the transformers by taking it out of standby.

Mr. Agedhorse: Our techs like your amps. They call them well thought out and easy to work on. It'll be interesting to see what comes out of your new affiliation.

Mugre
 
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