[thathertz]

[size=large]Does anyone have a copy of the MPX3 schematics they could PM me please?[/size]

 

[Uncle Erik]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Same here. They just won't budge.

Try inserting the allen key into the screw, then heating the key with a lighter or a propane torch. It'll cause the screw to expand, often breaking the grip of whatever is keeping it locked in. It'll also loosen any dried oil that's keeping the screw in place.

 

[PhilS]

I was able to get my Supra open. I bought one of the 90 degree allen wrenches and used it the short way with pliers. Here's a few pictures. I would appreciate any comments on the likelihood it will blow up. Feel free, of course, to comment on other issues you see with the amp, but since this thread is primarily concerned with safety issues, that's what I like people to focus upon. I sincerely appreciate any help anyone can give.

FYI, I bought this from Mikhail in August2004. I think this is one of the earlier Supra models, before his business really started taking off. I recall that he did not even have his website up yet.

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[kevin gilmore]

Looks like the basic MPX3 hand wired model.

I would put some 100k 1 watt resistors across each of the juice caps.
Other than that if you don't have any problems with it leave it alone.

schematic
http://gilmore.chem.northwestern.edu...ursuprampx.jpg

 

[PhilS]

Thanks, Kevin. Based on what you see in my amp, is the need for resistors a critical one, like there is a substantial danger of an explosion if not done, or more or less a safety recommendation, sort of like keeping your seat belt fastened in an airline in case you encounter any unexpected turbulence -- or something in between?

I'm trying to figure out how urgent it is to have this repair done.

FWIW, I hereby release, acquit, and discharge from any liability anybody who renders any advice or opinions on this thread concerning my amp, safety issues, recommended improvements, etc.

 

[penger]

Quote:

Originally Posted by moonboy403 /img/forum/go_quote.gif Is that the Platinum version?

It is the Platinum version that has/had? an additional power supply (supposedly 14 amp, but when I opened it up, it was not) that was supposed to enable it to drive 6528 tubes, but according to a discussion I've had with other members that turned out to be not the case.

 

[kevin gilmore]

Quote:

Originally Posted by PhilS /img/forum/go_quote.gif I'm trying to figure out how urgent it is to have this repair done.

That really depends on what the value of the unregulated B+ is
and what the actual values of the juice cans are. For example the
B+ could be about 350 volts, but those could be either 250,350 or
450 volt caps. You have no way of knowing without taking the
outer heatshrink off the caps.

If they are 450 volt caps with a 350 volt power supply you are safe
in any case. But really about 10 minutes and $2 in parts is a great
idea, especially since all the power caps would be automatically discharged
if left unpowered for 30 minutes.

The energy stored in the output caps will hang around a pretty
long time however.

 

[Uncle Erik]

Phil, I'd pu the resistors in just to be safe. Amps can be lethal, start fires and destroy equipment. You might be able to get away with running like this for years. However, when the results are potentially this bad, you should take every caution. I don't mess around with my guns, either. I follow all the safety precautions and treat them like they're loaded even when I just unloaded it. Same with the car - if there's anything that might detract from safety, I fix it ASAP. Other stuff, like a watch I have that started running slow, isn't a big deal. It needs to be cleaned, but I could wear it for two or three years with the worst potential outcome being that it stops altogether. An amp, gun or car can kill you if you neglect it. So maybe you'd get lucky and maybe you wouldn't. Do you want to roll the dice?

I can't vouch for him, but just stumbled across a guy named Jeffrey Angus who runs Stay Connected in Lennox. Supposedly, a tube guru who runs a repair shop. I'd at least give him a phone call and see if he'd like to take a look.

 

[PhilS]

Thanks for all the advice guys. I really appreciate it. I think I will try to find someone who can check it out and add some resistors. I found some information on Jeffrey Angus and will give him a call. Any other ideas on repair shops, especially repair shops in Southern California (I'm in South Orange County) would be great.

 

[fdhfdy]

Never know that owning a valve amp would be so dangerous, thanks for the info

 

[thathertz]

Cheers Kevin!

Quote:

Originally Posted by kevin gilmore /img/forum/go_quote.gif Looks like the basic MPX3 hand wired model. I would put some 100k 1 watt resistors across each of the juice caps. Other than that if you don't have any problems with it leave it alone. schematic http://gilmore.chem.northwestern.edu...ursuprampx.jpg

 

[nurxhunter]

Withdrawn. All I will leave is remark that........

Let's hope no one DIYs.

 

[Happy Camper]

The flames, they do get fanned.

 

[mrarroyo]

I hope I can get some help for my MPX3. It was upgraded (allegedly, have not open up the transformer enclosure to verify) w/ the Supra transformer and two (2) 2,400 uF power caps. Enclosed are pictures I took after I received the unit back from Mikhail.

Kevin Gilmore, where exactly are the 100k ohm 1 watt resistor to be installed at? I will not do the work but would like to know if the go across the +/- terminals of each of the caps. BTW my unit which I have had for about 15 months has run fine w/ no noises (yet) nor any heat issues.

Thanks for your help.

 

[takezo]

isn't that a bleeder on the 390 uf cap in phils's pic? i'm wondering why mikhail didn't do it
for those giant caps?...