Peavey XR600 series 400R

[Chaffeekid]

Hi Everyone, I'm Back..... Well picked up this Amp/mixer for 75.00 and of course it pops fuses. Searched the forum for the model and turned up quite a bit of stuff. Checked the output transistors and 2 were shorted, collector to emitter.

Ordered MJ1500G's from Mouser so they are on the way. Can't find any other items burnt or that appear to be at end of service life, other than the whole thing Now along with this I got a Peavey cabinet with 6 10" speakers in really great shape, this thing is really big and almost got a herina trying and suceeding in getting it up here in my repair area, yeah I'm upstairs.

The speakers work at least I am told they do. I am going to get this thing working and take it to the Church where it will get some use.

By the way, Thanks to Enzo for the help on the old TNT100 its still cranking out the bass on the Chruch stage.

Will post some more when the parts get here from Mouser and I get them installed.

Anything Else I should check for point it out to me, I could sure use a parts placement diagram for this old XR600 series 400R if anyone has one.

Thanks again.
Jim

[Enzo]

There is no layout for the old stuff. I eventually would take a schematic and assign numbers to parts - Q1, Q2, Q3, etc - then make a poosition chart of the board. In cases where there were more than one of a thing - like EP430 or something - I'd have to determine which was which but what they connected to.

[Jazz P Bass]

I have a strange copy.
Half of the pages are upsidedown..
With layouts.

[Enzo]

Cool, fun to see the tech scribbles. That layout is for the 400B/G amps, the schematic on the first page. The older 400 series amps on the last two pages, had the output transistors mounted on the rear panel, ther was no power transistor board. I still have not seen a layout for those.

[Chaffeekid]

Hey Enzo and JP, Thanks I have those schematics, I sent a request to Peavey Customer service and got that and also a hand made up overlay. I am going to try and attach it so everyone else can have a peek. Really love those guys and gals at PeaveyNever tried to upload a file so hope this works

Jim
400R schematic.pdf

400R Schematic and layout

[Jazz P Bass]

That is good info to have.
The hand drawn layout looks like my stuff

[Chaffeekid]

Update. I replaced two SJ6357's with MJ15003G's. The unit came on, but no output, i.e., no sound out of the speakers, (plugged into a speaker cabinet). Checked for the + - 15 volts for the front panels, had only a few 10ths of a volt.

Pulled the EP430 and 431 from the board and replaced with a TIP30c and Tip31c. Checked the 1 and 2 watt resistors, both were within speck. Checked the 4003 diode between the 10Watt resistors, pulled one end as it didn't check right, after raising one end found ok.

Plugged the unit in, and found the plus and minus 15 volts on the four pin molenx connector right corner of the board. When I plugged it in there was a spark and a little magic smoke for a millisecond from the 31c base pin. Still have the plus and minus 15 volts but a LOUD humm from the speakers. Havn't replaced the 31c yet as I don't want to burn one.

After about 5 minutes the 2 watt resistors will fry an egg and the back plane with the output transistors is really warm/hot. Unplugged it.

So something is still out of speck and I'm not sharp enough to find it without your help. Oh did I mention that while I had it on, I plugged in my bass guitar and the sound was AWESOME, however the humm was very loud and with it generating that much heat we wouldn't need a heating system in Chruch

Ok, some observations, 25.3 volts on the speaker terminal,,,HMMMM, have +54 volts one side of the 250 Ohm 5 watt and 24.42 on the other. Almost the same on the minus side, -54.2 one side, -27.35 on the other. The voltages on the legs of the 30c and 31c are 16.08 +- on the emitters, but only 24 and -27 on the collectors. Base voltage on 31c is 15.6 and on the 30c it is 16.10.

There is only MV's input terminals on the front panel. The Tip31c and the Tip30c are getting very hot, help help help

Waiting for some pointers from my mentors Thanks Guys

Jim

[Jazz P Bass]

Don't know where the 'spark' came from but it sounds like you must start from scratch.
Assume nothing.
Check everything.

[Chaffeekid]

Any Help Enzo? What would cause the 24volts on the speaker output? Where should I start?

Thanks Jim

[buffalono]

I'm working on one of these too. There was a fried resistor on one of the power rails that was burnt beyond recognition. It turned out to be a 4 ohm resistor, at least according to my tracing out of the circuit, I think it was used as some kind of fusible link. I went through the schematic with a highlighter marking tracing it out and marking marking the circuitboard and the schematic. I'll take a picture of it and post it, it may be of some help.

[Chaffeekid]

Hey, thanks for the response, sorry I am so late getting back to you, man we had some storms around here, no damage to our home or Chruch, prayers to those who lost everything.

Yes, I also found the 4.7 ohm resistor open, replaced it with the only one I had, which is a 4.3 but 1 watt, better rethink that if it is used as a fusible link
Still have -24 volts showing up on the speaker output. I am tempted to trash all the 430's and 431's and replace them with tip30s and tip31c's. I am also going to order some of the 13886 dual diodes from mouser and replace them. I had two shorted output transistors SJ6357's (shorted emitter to collector) on the backplane.

The Tip30c and Tip31c in the power supply get very hot so something is still on the fritz. I want to get this thing going to use it in the Church, along with mine I also got a large peavey Cabinet with 6 10" speakers and it sounds awesome with my base guitar, I think I can bust windows with it

Anyhow, that's where I'm at with mine. Would love to see a pic of yours. Did you get the hand drawn parts placement guide and schematic that I posted?
Thanks
Jim

[Jazz P Bass]

+24 volts on the output indicates that the output section is conducting.
This is basically a Class B amplifier.
It 'should' conduct nothing (sans Class A idle bias)
There are voltages marked all over the schematic.
Use them.
In you are not comfortable powering up an amp that is obviously failed, build yourself a 'lamp limiter'.
Google it or use the Search function above.
I think you should take a break & then go back in a statically test all of the transistors.
Something is off.
Throwing parts at it it will not fix it, unfortunately (well, maybe if you get lucky)

[Chaffeekid]

What would be the result of a failure of the 13886 dual diode on the back plane, in the center of the 10 Watt resistors? I ordered two of these from PV, whew 11.02 each wow.
Jim

[Chaffeekid]

Well, guess its time to give up on this one, I've tried everthing yep, voltages are not to spec in some areas, 20 plus volts on the collector of the ep430's, -9 volts on the 761's but I am not a tech, so I guess it's dumpster time, or maybe I'll take it out back and put a couple of 12gauge slugs through it, should be good for a laugh

Thanks guys
Jim

[Jazz P Bass]

Not trying to be snide, but if you give up on this amp, don't even think of trying to repair another brand.
All of the necessary voltages are marked on the schematic.
This, my friend, is rare.
I do believe that the amp is repairable.
As far as solid state output sections go, this one is simple.
I don't think that you fully grasped exactly what a solid state output section does.
Circuit group by group.
Kind of a shame that you are bailing as you where close.