Conrad Johnson PV 7 problem

[Peppe]

Hi,

I have a problem in my C-J PV7, it sometimes turn off and restart automatically. It means that I must wait 45 seconds about (warmap time) before the music restarts.

It is possible that the SPRAGUE capacitors (TVLU 1095) in the PSU are exhaust?

Someone got the schematics?

Thanks in advance

 

[Peppe]

The cap on the left is Spraugue TVLU 2925, are they still in production?

 

[SY]

You can certainly still find equivalent Twist-Lok electrolytics, but at the cost of not being "vintage," one can replace them with more modern caps of the same capacitance and voltage. Look for 105C rated capacitors. You'll be surprised at how much smaller we make them today.

 

[Peppe]

Thanks SY,

do you think my problem are the caps?

Do you have a favorite Twist-Lok capacitor producer?

Cheers

 

[dhaen]

In my experience, Conrad Johnson will email you a scan of the schematic if you ask them nicely.
When asking for schematics it normally it helps to give the serial number as proof of ownership.

 

[SY]

Thanks SY,

do you think my problem are the caps?

Do you have a favorite Twist-Lok capacitor producer?

Cheers

Possible, and I'd replace them anyway, but it's more likely in the soft-start/mute circuit or the regulator. But bad caps can still be the root cause.

I don't like Twist-Loks in general, so that's like asking me about my favorite rap artist.

Dhaen's point is well-taken: get a schematic, and troubleshooting will be much easier.

 

[moamps]

Hi Peppe:

You can find the schematics of the PV6 and PV10 versions here
http://www.drtube.com/audioamp.htm . The schematics should give you a pretty good clue as to your preamp.. From what I can tell, mulfunction may be somewere on the primary side of the transformer (if the "pilot" lamp turns off at the reset moment) or inside the "delay output on" circuitry.

Regards,
Milan

 

[anatech]

As I recall, they were using film caps for the B+ filter. Lower value of course. Also, every CJ I've looked at had the heater filter cap opening up. Check that first.

-Chris

 

[Peppe]

In my experience, Conrad Johnson will email you a scan of the schematic if you ask them nicely.
When asking for schematics it normally it helps to give the serial number as proof of ownership.

Ok, I'll try and will report the result...

Possible, and I'd replace them anyway, but it's more likely in the soft-start/mute circuit or the regulator. But bad caps can still be the root cause.

Sure, I will try to find the caps anyway

From what I can tell, mulfunction may be somewere on the primary side of the transformer (if the "pilot" lamp turns off at the reset moment) or inside the "delay output on" circuitry.

Yes, the led turns off at the reset moment.....

As I recall, they were using film caps for the B+ filter. Lower value of course. Also, every CJ I've looked at had the heater filter cap opening up. Check that first.

All suggestion are very important for me. It's my first time I decide to repair a my object, I just finished my first DIY-job (Aleph30) and now the pre decided to stops working......ARGH!

Maybe I will ask a friend of mine to help me in this job....

I want to thanks very much all you guys for suggestion

Regards

Peppe