The sad SAD1024A

[Dan N]

Hi guys,

I just bought a broken Deluxe Memory Man from ebay. Of course I was hoping it would be a cheap and easy fix.



Oh well...

Guess I better find out what blew these suckers up before replacing them.

Dan

[ExpAnonColin]

OUCH!

[Peter Snowberg]

Ouch! is right!

I'm going to guess that was a power supply mishap.

Best of luck on your repair. That really brings new meaning to SAD 1024.

Good luck,
-Peter

[phillip]

Holy crap!  Those things must've gotten HOT to burn holes through them like that!

Does the Memory Man have a built-in 120V power supply?  If it does,  I would suspect something in that area...that would be about the only thing that could send enough juice through there to fry those chips that bad.

If it has a DC power jack, then someone could've plugged in a wall wart that had way too much voltage and current.

Phillip

[Hal]

at least one of 'em looks good :-D

[Fret Wire]

The 1024 on the far right looks like it has two pins cooked off. WOW! $15 a pop for these bad boys! I feel your pain :cry:  With some good hunting, you may luck out and find a quad of these cheap.

Is there any evidence of ametuer hacking in the circuit anywhere? Maybe this guy used his 5000W camp generator for a wall wart.

[Dan N]

It does have it's own power supply. I get 34 VAC from the transformer secondary, and a DC power supply of 15VDC. The only voltages I get from the delay chip sockets is about 4.5 volts on pins 2 and 15. The other opamps are getting the 15 volts.

No hacks as far as I can tell.

I have to trace this thing a bit before I try to do anything.

That one good looking chip on the right looks like it was a replacement. While not exploded, it has a carbon trace jumping the pins and it's socket was really powdery with carbon.

I have 2 1024's still in their Radio Shack bubble package so I'll only need 2.

Funny, I can dive right into a live tube amp without much fear, but working on this little box with the AC on just scares me!

[niftydog]

I can work near 25kV all day... but the second something goes bang, or there's smoke, or visible damage like this, it gets a little edgy around the workshop!

Just something about that subtle reminder of the power of electricity...

electronic eng. humble pie recipe;  hook up a 50V cap, backwards, to 200VDC and stand well back!

[drew]

I'd cut your losses, re-ebay it, and get a used-but-working one instead! I would cry if you blew up those 1024s


drew
www.toothpastefordinner.com

[Mark Hammer]

The folks who were pedalling a "reworked " MXR Analog Delay with a daughter board using a PT2399 had the right idea.  Not only is it going to be expensive to find and buy a quad of the 1024s, but  the sound quality will not likely be much better, nor will the delay time be any longer.  Does *anyone* really want to contend with 4 sets of trimpots?

[Impaler]

Looks like one of the military's scatter bombs went off in there