M1.0t died with a pop

[JBJR]

Hi guys new to the forum, just found it a week ago! I have 2 M1.0t amps and 2 Silver 9t's. Looking to pick up a few more when the price is right.

Ok, my one 1.0t died on me a while back and didn't think I'd ever get it fixed, maybe with a little help we can get it going again! I have read the other thread and my problem is different. Turned it on and heard a pop, and no meter lights are on now, but, can still hear the slight buzz of the transformer. I also only have a multimeter. What should I check first? Thanks

John

[Robert R]

We get more new members this way! Welcome to OCCD land.

In the M-1.0, rule number one is: Do not under any circumstances jumper across the triac (TR 401). You will destroy the whole thing.

Rule number two: In this amp, a problem in one channel often shuts down both, so don't automatically suspect just the power supply.

Now, to answer your main question, Ohm-check (Rx1 scale) all the power transistors, 10 on each end, for shorts. If I needed to tell you to have the unit unplugged to do this, you probably should send it to Oregon for repair. Check each of the three leads to the other two, both ways (i.e. reverse the ohmeter leads and do it again. That's 12 tests per transistor!) Half-scale readings are normal, near-shorts are not. Report results and then we go on from there. If there is a question, the other channel (other end) should read about the same; a big difference indicates a problem.

Also, for possible later use, determine the version of M-1.0 you have. Is there a switch on the back for mono use? That's the "non-inverting" type. No switch= "inverting" type - slightly different schematic. Note: the switchless types can still be wired for mono use.

Robert R

[docadillac]

Welcome to the forum. RichP714 is the resident 1.0 expert. I'm sure he can help you out.

[RichP714]

Sounds like Robert R got to this one before I woke up.
I'd only add that:
Carver magnetic field power supplies don't operate like normal power supplies, a local electronics repair shop is likely to destroy the amp by shorting across the triac in an attempt to 'jump start' the power supply, as Robert R mentioned.

Depending on your comfort level with working on electronics, you have a few choices:

send it in to a Carver aware shop like hitech, which charges at flat fee near $300; great service and you'll get an as new amp back.

Send it to me and I'll do a Mk II modification to it:
viewtopic.php?f=39&t=5673
you'll get back a better than new unit, and if you do the Mk II opt 002 it'll be the most powerful Carver excepting the silver 7t/9t and tfm-75

Fix it and/or Mk II modify it yourself; guys like Robert R, JVT, a couple of others and myself are always here to help someone who's not going to hurt themselves or the amp.

You're in a good position, in that at least you know the mag coild isn't dead. Good luck

[Robert R]

Hi Rich,

Don't mean to poach your territory, you're the best on these. Just thought I do the introductory stages on this, since you are so involved with the AMP FROM HELL, (actually Uruguay, which is probably worse). If it gets hairy, I'd hand off to you in a second. As you know better than anybody, half the time the new guys never even post a reply, and your time is all wasted anyway...

Rob

[audiophile101]

I would have Rich MKII both of your M-1.0t's. His work is more than impressive!

[RichP714]

Glad to have you on this Robert...the more the merrier

[snarffydoggy]

All right, another learning class and 2 instructors for the price of one!!

[brit01]

Just thought I do the introductory stages on this, since you are so involved with the AMP FROM HELL, (actually Uruguay, which is probably worse)

Is there another member in Uruguay? Can't imagine you're talking about my baby otherwise I'd be deeply offended

My amp when finished will be just sounding so sweetttt.

[JBJR]

Thanks for the replies guys! I've been around reading for a while so I know about the triac and repair shops and how carver amps are different. I'll check the transisters and get back. The Mk II mod sounds awesome, sounds like i may send them out to sometime soon Rich!
I am somewhat comfortable around electronics, work on and mod Marquee crt projectors mostly the 9500!

John

[RichP714]

Thanks for the replies guys! I've been around reading for a while so I know about the triac and repair shops and how carver amps are different. I'll check the transisters and get back. The Mk II mod sounds awesome, sounds like i may send them out to sometime soon Rich!
I am somewhat comfortable around electronics, work on and mod Marquee crt projectors mostly the 9500!

John

Glad you found us, and welcome! Post your findings on the output transistors and we'll help you out from there

[JBJR]

Oh, both of my 1.0's have the mono, stereo switch.
Nice work Rich, I've already replaced the binding posts with similer ones, and was going to put a newer bigger power cord in before the pop!

John

[JBJR]

Ok, finished checking all power trans. Q128 is shorted.
All the others read the same as their counterparts across the board except Q130.
It is reading 49 when pos is to E and neg is to B and reading the same reversed. Q129 is reading 2.1 both ways.

John

[Robert R]

Confusion: did you mean to say that 128 is shorted and 129 reads 2.2 ohms both ways? Those are in opposite channels. The odd numbers are left, the evens right.

Possible to blow both channels at once, but need to confirm the numbers before proceeding.

Q128 = 2SD1718
Q129 and 130 both = 2SB1163
All of these probably would have an "A" suffix.


Rob

[JBJR]

Hi Robert sorry for the poor explaination. 128 is without a doubt shorted. Q127 opposite channel is fine. Q130 next to Q128 is reading 49.9 when probes are placed on B and E, same reading when reversed. Q129 opposite channel to Q130 is reading 2.1 when probes are placed on B and E, same when reversed. Sorry, know nothing about amps!

John