2 Questions about setting voltage

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2 Questions about setting voltage

Postby Doppleganger » Wed Apr 29, 2015 6:13 pm

I'm at the voltage setting phase (step 46) and I have a couple (probably silly) questions:
1. which pin on J1 is pin 2? I don't see a description or label anywhere.
2. When turning R39, do you turn it clockwise to adjust down? It's just sitting on 46.7 volts and doesn't move at all either way I turn it (assuming I'm on pin 2).
Thanks.
Doppleganger
 
Posts: 6
Joined: Wed Apr 29, 2015 6:06 pm

Re: 2 Questions about setting voltage

Postby Doppleganger » Mon May 04, 2015 4:24 pm

OK, I've checked some more things out. I have 2 modules with the same readings. Both read 46.7 volts and r39 does nothing to change that. I can find no parts in the wrong places, no capacitors oriented wrong. The test point on C26 does read 24v, but the other test point at R40 reads 0v instead of 3.75v. I can find no heat sync or anything else that shouldn't be touching the chassis. I took readings for Q1-Q6: Q1- C=1.9, B=2.4, E=3.9, Q2- C=13.1, B=3.9, E=3.2, Q3- C=12.4, B=13.0, E=21.8, Q4- C=0, B=0, E=0, Q5- C=.4, B=1.0, E=.4, Q6- C=.4, B=.4, E=0.
I'd really love some help with this.
Doppleganger
 
Posts: 6
Joined: Wed Apr 29, 2015 6:06 pm

Re: 2 Questions about setting voltage

Postby Doppleganger » Tue May 05, 2015 5:28 pm

-I double checked part values again and re-flowed every solder joint on the board with no change.
Doppleganger
 
Posts: 6
Joined: Wed Apr 29, 2015 6:06 pm

Re: 2 Questions about setting voltage

Postby Doppleganger » Tue Jun 02, 2015 4:07 pm

-Ok, I haven't had much time to work on these for a couple weeks, but I figured out a couple things:
1.- I was not sent parts L3-L6 for either kit. Since they are not covered in the install instructions, I didn't think they were necessary. That was no issue though. I contacted the SSA and he sent them right out. Installing them didn't solve my issue.
2.- I've been reading some more recent post that describe my issues and I re-soldered the grayhill transformer leads again and now I can set the voltage. Unfortunately, when I plug a mic into the preamps, they have extremely low input gain (I have to turn them all the way up to hear anything) and they sound a bit distorted.
Ideas anyone? I have reflowed all solder joints already. Would this have anything to do with the jumpers on J2 or J5 and J6?
Doppleganger
 
Posts: 6
Joined: Wed Apr 29, 2015 6:06 pm

Re: 2 Questions about setting voltage

Postby Doppleganger » Sun Jun 07, 2015 2:52 am

-I finally got both units working. It was the input transformer leads. They sound great now.
Doppleganger
 
Posts: 6
Joined: Wed Apr 29, 2015 6:06 pm


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