So many problems with my DRRI !

[Wil]

Hello everyone, I'm totally new to this forum but I already came across a lot of threads on Music Electronics forum and learnt a lot! So thank you everybody !
Here's my story :
I bought a used 1999 DRRI online, I did not test it out before buying, it came from France and I'm living in Belgium. It has Mercury Magnetics Transformers. I've been trough a lot, a lot lot of problems with this bad boy. I changed all the capacitors, tubes, optocoupler, etc...
The thing that got this amp back to life was changing all the electrolytics (I first changed the filter caps with no better results).
It sounded great but when I turned the intensity pot a little, I had volume drop, so I changed the optocoupler. I still had the problem and the tremolo was even weaker.
I checked every single resistor value and found some that were interesting... Two 100ohm measured 50ohm (I guess they were in parallel but I changed them anyway and they still measured 50ohm...) and in the tremolo circuit I changed a 2M2 resistor that measured approx. 330k and it still measured 330k...
But after that, I don't know why, maybe this amp only wants to p*$$ me off but it was way weaker and thin sounding than before... My Blues junior was louder. So I took my multimeter tested out a couple of thing and accidentally touch pin 7 and 8 of the rectifier at the same time (amp was on, standy too) which blew the fuse and made a cool lightning... I'll buy a new fuse tomorow. In the meantime I cross my fingers, I hope the rest of the amp is alright. I've always dreamed of a crystal clear Deluxe Reverb and I just can't achieve this.
I may sound a little blurry in my explanations, but if anybody can help me troubleshooting that evil amp, I would be very pleased ! Any piece of advice is welcome. (I'm leaning toward building a brand new PTP circuit in it... I can't stand troubleshooting this amp all the time...). So the main question is : What could it be ?
Thank you very much!

[soundguruman]

replace the fuse and see if it works
you shorted the heater to ground or something.
If it works you can probably replace the tubes and adjust the bias.
But without test equipment etc, it's harder to troubleshoot
You may be measuring this in the wrong way, it seems.
if the fuse blows again try replacing the rectifier tube

[JoeM]

Ouch. First of all stop randomly changing parts that arent defective. Parts measured in circuit can be misleading - as you're finding out. Do the simple things first. Have you substituted different tubes?

[Amp Kat]

How much would it cost you to send it to a tech who has the proper tools to troubleshoot it and solve the problem for good ? Authorized service center ? Do you have a schematic, scope and signal generator ? Without that your chances could be slim and none if there is something wrong not visable to the naked eye which it very well could be. Cold solder joint ,hairline trace fracture,wrong value, tube socket ect.....

[Wil]

Can you tell me where I should measure ? What are the most relevant test points ?
The two wires that got linked for a brief moment are a yellow and a red one. They both come from the PT and that's what blew the fuse.
Is it serious, doctor ?

[Wil]

Only thing I have is a multimeter. I changed parts with the same value, I don't think it's a resistor or a cap that fails. The sockets look tight but I resoldered a couple of them to be sure. There's no amp expert in the area except a guy that ask a lot for not much... Here's his website Luthier LiEge - Depannage ampli a lampes - Tubes amps service
Do you think it's a good idea to go PTP ? It's very expensive for results that aren't always what we would have expected.

[Wil]

Also! My newer JJ power tubes made a very strange noise when I was switching the standby off. The amp was squealing during half a second and it happened to be the power tubes... So I put older groove tubes that sound like... you know what!

When I have time, I'll resolder every solder joints, change the tube sockets and triple check every values (but I don't think they're the problem because the amp sounded nice for a week or two, before I changed the optocoupler and probably broke something, after that, the amp wasn't clear anymore, nor loud, I'd say thin and slightly distorted which is very very unpleasing).

[Cygnus X1]

As suggested, a more logical approach should be taken.
You risk breaking things that aren't broken (yet).

[Wil]

I want to put numbers on my problems. But I don't know where to measure "relevant" voltages.

[52 Bill]

I want to put numbers on my problems. But I don't know where to measure "relevant" voltages.

Get a copy of the schematic or the service manual for this amp. There will be voltages and test points for you to check. Post the schematic here so everyone can show you where to take relevant voltage readings.

[Wil]

Get a copy of the schematic or the service manual for this amp. There will be voltages and test points for you to check. Post the schematic here so everyone can show you where to take relevant voltage readings.

http://ampwares.com/schematics/65_Deluxe_Reverb_RI.pdf

This is the one I use. My amp is from 1999 and the schematic is from 1993, I don't think they added any new features or component during those years unlike the recent production with the newer tremolo unit (which to me is a real mess).

EDIT : I've just found pictures of a 1999 Deluxe Reverb http://vintageamps.com/plexiboard/vi...hp?f=8&t=88984
At that period Fender went from green board to cream board. I know the Blues Junior too. So my DRRI is a cream board, I don't know if they changed anything with this transition (they were major changes on the blues junior, but don't know for the DRRI).

[Raybob]

http://ampwares.com/schematics/65_Deluxe_Reverb_RI.pdf

This is the one I use. My amp is from 1999 and the schematic is from 1993, I don't think they added any new features or component during those years unlike the recent production with the newer tremolo unit (which to me is a real mess).

On that schematic, you will find voltages shown at various points. You should be within 20% of volts specified, everywhere they are spec'd. Start with voltages: pins 1,3,6 & 8 of preamp tubes, and pins 3,4,5 of power tubes.

[Wil]

Thank you. I'll do this this evening (it's 9:30am here in Belgium).

[Raybob]

Thank you. I'll do this this evening (it's 9:30am here in Belgium).

Sounds like you may be new at this. Be careful. There are spots in there with 400+ volts, even unplugged. Safest if you leave one hand in your pocket, while other hand probes voltages.

[Wil]

I've made pedals first. I know how to solder, and have a bit of knowledge about tube amp but not that much, but I know those amp can be killers (not only when talking about tone, haha!). I learnt a lot from Bill Machrone and his Blues Junior mods but I only follow instructions. Thank you for the warning.