[kevin gilmore]

you have the diodes insulated from the heatsink with thermal washers and
a piece of plastic on the screw so that the heatsinks are not electrically hot??

datasheet on those diodes ??

The circuit board is scortched pretty good, at least i won't get any worse.
The circuit lands on the other side should be ok.

 

[mrarroyo]

Dr. Gilmore those are the diodes (625-FES16DT-E3) you recomended via PM. I bought them from Mouser.

FES16DT-E3/45 Vishay Semiconductors Rectifiers

The specs are at: http://www.mouser.com/catalog/specsheets/FES16JT.pdf

So, do I need to open the amp up and remove the insulating film? Do I use paste to enhance the transfer of the heat? Thanks.

 

[mrarroyo]

Ok, opened the amp and carefully removed the insulating film which I thought was to aid in transfering heat from the diode to the heat sink.

I guess not having as good a heat transfer w/ the correct paste is better than having a piece of insulation.

 

[kevin gilmore]

The silicone insulating film is always a good idea.. That and
the insulating washer on the screw. Otherwise the heatsinks would be
electrically hot and it they touch, they can short out.

Put the thermal washers back in, and make sure none of the heatsinks
touch each other. Especially the two on the right. Bend parts of the
heatsinks if necessary to make sure.

The two on the left have the cathodes tied together anyway, so its
not as much of a problem.

 

[mrarroyo]

Shoot, I threw away the insulating strips!

Man, I do not seem to be doing this right ... At least the thermal washers are installed. Thanks.

 

[Bolder]

PhilS Supra has been repaired/updated/made safe.

Here is his picture of the unit.

100K 2 watt resistors were placed across the juice can caps. The rectifier diodes for both high voltage and filaments were replaced with HexFREDs. The transformer wiring through the chassis had additional insulation added to it.

I also cleaned up the wire routing and dressed everything up.

Using VT-231 for a driver and 6SN7s for outputs into a pair of HD-600s, everything sounds very sweet. This amp should be good for quite a long time.

 

[Frihed89]

Miguel, You replaced the filament diodes, but did you also replace the high voltage diodes? I notice you don't have the high power option, like I do, so perhaps you don't have a problem. I think I need to replace the diodes and/or simply do away with the high power option. (I have bigger filament diodes than you did, but may replace them. I am not sure how to read them). I will be getting back to this after RMAF.

 

[mrarroyo]

Hi Frihed89, I would not even know which are the high voltage diodes!

The ones I replaced were the ones suggested by various readers. I will tell you the amp is working very nice and I believe cooler than before. Cheers.

 

[TreAdidas]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif According to the cursory review/evaluation of the pictures I posted at Head-Fi Dr. Gilmore indicated I needed to install bleeder resistors on the two large power caps. Here is a picture of the installed resistors across the poles of the power caps.

What is the part number for these bleeder resistors?

 

[Frihed89]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Hi Frihed89, I would not even know which are the high voltage diodes! The ones I replaced were the ones suggested by various readers. I will tell you the amp is working very nice and I believe cooler than before. Cheers.

The ones you replaced were the 4 on the lower right, correct? The high power diodes are on the upper right - 2 of them- one is numbered D51. Dr. Gilmore told me that I should check the size, which I haven't done yet because the amp and I are in different places.

I like your work and am glad you are happy.

 

[fliatfir]

will be getting back to this after RMAF.

 

[junerpp]

..

 

[mrarroyo]

Quote:

Originally Posted by TreAdidas /img/forum/go_quote.gif What is the part number for these bleeder resistors?

Those were 100Kohms 1 watt resistors if memory serves me right. But you could use up to 150Kohms 2 watt resistors.

Quote:

Originally Posted by junerpp /img/forum/go_quote.gif Hi, this is the internal pics of my MPX3 Slam SE with supra transformer upgrade. Anyone can help to point out the potential danger? Thanks for any useful info.

You should post a larger size pic. Not being an expert I can see your board is getting cooked by the diodes (lower right corner) and you should install bleeder resistors on the large power caps. You should also remove the transformer cover to see what kind you have installed.

 

[junerpp]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Those were 100Kohms 1 watt resistors if memory serves me right. But you could use up to 150Kohms 2 watt resistors. You should post a larger size pic. Not being an expert I can see your board is getting cooked by the diodes (lower right corner) and you should install bleeder resistors on the large power caps. You should also remove the transformer cover to see what kind you have installed.

Hi Miguel, Thanks for suggestion. I will try to take more pics.

 

[seasterl]

Sorry to be somewhat off-topic, but I haven't had time to read all of these posts yet. But I did read the very first post, and noticed the rat's nest of a very poor design. I cannot believe I spoke to the designer (Mikail??) a few years ago and how badly I wanted one of these amp. Has anything changed? Did the OP somehow receive a prototype model? What's the top (non-Chinese) tube amp these days that a serious listener should consider to drive my AKG 701 and HD600 phones?