Peavey eddie van halen amp.

[catstrat]

I need some help from you fine folks. I have a Peavey amp that just has Eddie Van Halens signature on the front panel and nothing else. Peavey sent me copies of the schematic but i really need the layout for this amp. The layout they sent is not the right one. Is there a difference between a 5150 and an Eddie Van Halen amp? I thought they were the same. Thanks

[Jazz P Bass]

How about a pic?
I do not recall seeing a signature.
Simply EVH in the lower right face plate corner.

You could try the Peavey 6505.

[tedmich]

There is the EVH 5150 combo as well as the 5150 Block letter and 5150 signature heads. The head's power amp boards were changed and there are two versions
this schematic has both the heads power amp board layouts.
https://drive.google.com/file/d/0Bx4...ew?usp=sharing

if its a combo there are copies around

The 100 ohm 5w screen grid resistors on the PA board go bad all the time and are best replaced with 750-1k 5w versions, but you usually have to drill out the rivets on the tube sockets to get to them.

[drewl]

I usually find the typical intermittent PC board connections and ribbon cables.
Early versions had no bias adjust, later models did, most are biased cold from the factory.

[catstrat]

Peavey EVH

I talked to Peavey again and explained to them my probalem and she sent me all the schematics and layouts she had. The 5150 2 seems to be the right schematic with the right layout. This one has low volume. The sine wave from the preamp looks good but seems something is amiss going into the PI. I've cleaned the effects jacks and everything else that may cause this problem to no avail. The boards are bent into a U shape like the classic 30s and i don't know of any way to check for signal or voltages with the board in the chassis. I removed the boards and was going to check for an open resistor that way. It would be a lot easier if i could check this stuff on a live circuit. I guess i could by just re installing the boards and doing the best i can. I checked the plate voltages on all of the preamp tube sockets after removing the tubes and they seem fine. Couldn't find any cracked or broken solder connections either. I'll just keep looking and any other advice any of you have, i'm all ears. Thanks everyone.

[tedmich]

6505! Bingo!
You've swapped out all the tubes right?

check all the SGRs and PS caps ?

[catstrat]

5150

Hello. The customer put new tubes in it before bringin it to me. I tested the tubes and they all test good.I subbed a good o/p tranny and still low output. I'm looking at the PI circuit. Is this the same as a 6505? THanks

[Jazz P Bass]

What does the amplitude of the signal look like at the Pre Out jack? (amp maxed)
What does it look like at each half of the output tube grids?

[catstrat]

5150 low volume

The wavefrom the preamp was good strong and clean. Keep in mind, because of the way the boards are installed i can't get my scope probes into the o/p tube solder points to checkany waveforms or voltages.Unless someone has some advice on this. Thanks.

[g1]

I checked the plate voltages on all of the preamp tube sockets after removing the tubes and they seem fine.

This is a little unclear. Did you check the plate voltages with the tubes in or out? You will only get accurate readings with them in.

[Jazz P Bass]

The output tube AC grid voltages should be able to be checked directly at the socket.

[pontiacpete]

don't know if you problem is related or not but, have you checked out this thread?
I ended up taking all the boards out and jumping all the connectors to run the boards outside of the chassis. What a pain.
I certainly would like to know of an easier way of work on this amp.
Good Luck.

http://music-electronics-forum.com/t26407/

[catstrat]

Before the boards came out i checked the voltages with the tubes removed. The voltages all checked fine , a little higher than with tubes in. But no low voltage. The O/P tube bias voltage was good to. I'll check out the thread posted and see if they have any insight. You're right, these are a pain in the behind to work on.

[g1]

A low plate voltage will rise up to above the normal when the tube is removed as it is now an open circuit.
Without tubes is a good way to check for bias or signal on power tube grids, but for plate voltages you need them installed.
As you said you have good signal at the FX send, your preamp is probably ok anyway.
So on to JazzP's suggestion of checking drive signal at the power tube grids. You can do it with power tubes out.

[catstrat]

Peavey van halen combo.

Hello everyone. Sorry about so long to respond. My brother passed away on the 10th so we had that to contend with. Can someone tell me what Q1 is supposed to do. The reason i ask, after spending some time with the schematic i checked Q1 and Q2 and the source and drain test as shorted. The schematic says clamp to the gate. They're J 174s which i have in stock. I checked the amp with my scope again and it's the preamp that has the problem and not power amp. I ran a signal into the effects return and the o/p section sounds strong and has a good sine wave. I checked CR 1 and CR 2 and they check good. Thanks so much for your help on this. I've already pulled the board out again.