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**Enzo** · 12-16-2009, 05:15 AM

Disconnect the speakers, and work without them until we get it sorted. Set your meter to DC volts and measure voltage at the speaker jack or at the wires that would go to the speaker. Is ther DC that would be across the speaker? I am talking a number of volts, not worried about a fraction of a volt.

If not, then flip to AC volts - got as bunch of those I bet.

By the way, XL500 or XR500? And does the rear panel say something like 400BH or 260C? or look on the main powr amp circuit board on the solder side. Is there a board model # like those?

If there is no DC on the speaker leads, then plug something onto the power amp in jack to disconnect the preamp. AC volts gone?

**captainlee** · 12-16-2009, 05:57 AM

Hi Enzo,
OK can do will have all info for you wed with pictures and your request thanks a bunch.
XR-500 and series 260-c 130 watts@4ohms more to come. Cap.

**captainlee** · 12-16-2009, 03:07 PM

**Enzo** · 12-17-2009, 05:03 AM

Yes, I am familiar with the 260C board, and I own an XR500.

You have DC on your output.

The amp itself will operate without the front panel connected. SO leave the cables to the front off it for testing.

Power off and unplug. You have the large power transistors on the heat sink. Check each one for shorted. The casing is one terminal and there are two legs under each.

There are two smaller transistors on the aluminum finned things. Check them for shorts. Check the large rectangular tan colored cement power resistors for open.

And try a new TL074 in the 14 pin socket. Pay attention to which way it faces.

**captainlee** · 12-17-2009, 05:20 AM

Hi Enzo, Thank you for looking at my pics ect.

1. I don't know how to check the power tranisters I understand shorts just need to know the proceedure. do I remove those power transisters to check them or can I use the ohm meter to check the conections on the circuit board?
2. what is the TL074 and where do I get that part mail order place what is the name of this part is it a capacitor? Thank you, waiting for further instructions. Cap.

**Enzo** · 12-17-2009, 05:29 AM

TL074 is the black rectangular thing with 7 legs down each side. It lives in a socket. it is an integrated circuit, a "chip," and can be had where parts are sold. Places like Mouser. But really, by the time you try to order one 50 cent IC and pay shipping, you might as well drop by the local electronic repair shop and pay them $4-5 for one of them.

And that is about the only part on this thing that is changable without soldering on the board.

"Short" basically means "connected directly to." As in two or more of the three terminals on a transistor are now connected directly together inside - a not desired condition. Your ohm meter will tell you that.

And I don;t mean this unkindly, but we are fast approaching a point where it will get very difficult to lead you through this without some level of knowledge on your part.

**captainlee** · 12-17-2009, 05:55 AM

Ok I found the transister checking instructions no problem there.
i will get the other part.
I am still waiting for the schematic for this unit.
hang in there Enzo we will work this out.
I seems if some of the transistors are bad I will want to buy them at the same time and won't that fix the problem?
I will get back when i have done the things you have asked a few days.

**Enzo** · 12-17-2009, 06:31 AM

I never assume it will merely be a bad transistor or two. Certainly we have to worry about damaged resistors as well.

Here:

Attached Files

PV 260C '78.pdf (615.3 KB, 378 views)

**captainlee** · 12-17-2009, 07:17 AM

Ok Thanks again that wil help alot I will get to checking those parts and and get back to you with the results. Thursday. Cap.

**captainlee** · 12-17-2009, 03:37 PM

Hi Enzo, Here is the information:

2 of the 67376 power transistors bad RCA Q6 Q7 2N3773
1 of the heat sink transistors bad 039 5331 motorola VR1 NOT SURE WHAT THIS PART NUMBER IS?

All ceramic resistors show continuity.
The schematic is very useful Thank You. Are there any other checks to make before I order these parts? Cap.

**Enzo** · 12-18-2009, 02:44 AM

All four outputs are 67376. Th 2N number is probably a good sub, but the amp will be happiest with four identical transistors. If it were mine, I would just use four MJ15003 or MJ15024 from my stock. I buy them from Allied myself.

Or order some 70484140 from PV - those are MJ15003 in disguise.

5331 is a PV house number - it is basically a MJE243 Or order it from PV as 70405331

COnsidering what you are now replacing, check ALL of those 0.33 ohm 10w resistors for opens. Check 47 ohm R23 for open or for way off value. And check R20, R22 up near the 5531 on the schematic.

**captainlee** · 12-18-2009, 03:00 AM

i CHECKED THE CEMENT RESISTORS ALL ARE GOOD BUT I WILL CHECK THE ONES YOU HAVE OUTLINED.
CAN i BUY THOSE PARTS FROM YOU AND GIVE YOU SOME EXTRA $ AT THE SAME TIME?
PAYPAL, VISA,AM EXP?? YOUR CHOICE. tHANKS CAP.

**Enzo** · 12-18-2009, 10:25 AM

Thanks, but I am not really in the parts business.

Mouser and Allied haver no minimum order, and MJ15003 and MJE243 are common parts. Peavey has no minimum order either, and you would order by their part numbers, which I provided.

**captainlee** · 12-18-2009, 08:56 PM

Ok that's fine.I'm going to replace both vr1 and vr2 do you have the part number for VR2
I am going to use Mouser and Allied for the parts.

I'm noticeing that the part numbres at the suppliers have a "G" after the part number is that ok?
I am thinking of replacing all suspect parts.
Any tips on removing the old parts. I have a solder sucker and a pen style iron?
I can't tell how much your help means to me thanks again.

)

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