Paramour 1 Troubleshooting

[jeff g]

Yes, that is a reasonable conclusion.  IIRC, you swapped the tubes so it isn't a shorted heater.  That only leaves the transformer and input wiring.

Just to be sure first clip the two diodes, bend them so they are obviously open.  Do you mean remove them ?

That leaves the transformer with no load, no diodes and caps.  Try powering it up one more time and check the fuse.  If it blows, it is the input wiring shorted somewhere after the fuse or a shorted transformer.  It might be the trasformer - there was some 'minor' arcing during one of the tests.

Maybe Doc or PJ can give you resistance readings for the primary and secondary sides of the transformer. 

If the fuse holds then two caps, two diodes and a resistor will put you back listening to music.

 

[jeff g]

I'm pretty sure I've got the Hammond transformer - are the values I quoted before the correct ones?

Grainger - I'm not sure if it was clear in my quote, but did you mean to remove the diodes then test again?

 

[Grainger49]

Yes, the diodes probably cost 17 cents so replacing them is cheaper than replacing the caps.  I just wanted to prove that your transformer and associated wiring is OK. 

Clipping the diodes is faster than desoldering them.  You have narrowed it to the power supply.  This is another check to see if it is the transformer/wiring or diodes/caps/resistor.

 

[jeff g]

I removed the diodes - measured resistance at infinity

Tried firing up again - fuse blown.

Removed all PT wires- they test as follows:

Black-White 10.8 ohms
Brown-Orange 83 ohms
Violet - Orange 175 ohms
Brown - Violet 93 ohms
Green-Green 1.5 ohms
Yellow-Yellow 0.6 ohms

Black - Transformer housing infinity

all the secondaries seem low relative to the PJ post I quoted above.

 

[Grainger49]

Jeff,

I'm hoping it isn't the transformer.  Is it possible any one of those few wires from the incoming cable to the transformer has come loose and grounded?

My Paramours are the newest transformer (lugs under the chassis) so I'm thinking my measurements wouldn't help.

 

[Paul Joppa]

It sounds like a bad transformer to me. I wish it weren't too! I'm out of town, and I think Doc B is also at the moment. I'll email him. Meanwhile, make the same check on the other channel's transformer - that should eliminate other possibilities.

 

[jeff g]

the wires from the incoming cable seem ok.

I guess I can check the other channel - hopefully I won't monkey up a working amp!

if it is the transformer, could someone please recommend replacement options (keeping in mind that while the MQ stuff would be nice, it's not really in my budget right now)

 

[jeff g]

I checked the PT on the good channel - readings were different (and close the ones posted by PJ above)

Black - White 10 ohms (10ohms on bad ch)

Violet - Brown 411 ohms (89 on bad); should be 420
Violet - Orange 212 ohms (168 on bad); should be 220
Brown - Orange 199 ohms (79 on bad); should  be 200

So, is the PT shot?  Wouldn't some of the measurements be very low or open?

 

[Doc B]

Yes, it sounds like a partially shorted secondary winding. It will need to be replaced, and it will probably be wise to replace the rectifiers as well.

 

[jeff g]

thanks Doc.  I've got an order in for caps, rectifiers...

Do you have any suitable transformers for sale?  or recommendations ?

 

[elcraigo]

If Doc doesn't have a solution, I can help you out with used Paramour I power transformers. They are the 1st version of the power transformer, with colored wires coming out of the transformer. just send me a PM

 

[Paul Joppa]

We haven't used the Hammond for years; it was replaced with a custom Bottlehead. We'll get you working, there are at least three alternatives, but it's a little complicated - I'll post more later this week when I'm back in town.

 

[jeff g]

Thanks, much appreciated

 

[jeff g]

Paul - Just wondering if you've had a chance to look into replacement transformers?  thanks

 

[Paul Joppa]

Sorry, my last post was out of sequence - I missed some earlier ones while on vacation.

If elcraigo has a spare (must have been a replacement or upgrade at some time?) that would be the easiest. I'm prett sure Doc B doesn't have any, but my parts stash is so disorganized, there may be one in there somewhere. I'll look around too. Since it would be identical to the originl, there is no need to change the good amp.

The second option is to make a special order for the PT-2, our most recent Paramour transformer. It's out of production but we can still order small quantities. This would require some re-wiring and a different high-voltage supply - fullwave bridge vs. center-tapped in the Hammond. It's different enough that I would recommend changing both transformers, though that's not strictly necessary. It's not very complicated but we have not written down instructions for this.

The third option would be an experimental use of the PT-7 with DC filament supply - I don't recommend it because I have not tried it yet, and it's a major re-wiring.

 

[jeff g]

Thanks Paul.  Sounds like elcraigo might be my best bet, but please let me know if you find one in your stash. 

 

[elcraigo]

The spare power transformers I have are from the first version of Paramour I. circa late 2000 to early 2001.
They are the Hammond's.
They were removed to upgrade to the PT-2 power transformers so I could convert the amp to a SR-45.
Ping me if you want one or both of them.

Yes - the amps still work great 12 years latter