Author Topic: '74 Suitcase 88..Left Channel Out!? Arrrrgh!  (Read 6665 times)

Offline Sack

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'74 Suitcase 88..Left Channel Out!? Arrrrgh!
« on: May 17, 2005, 11:48:55 AM »
:cry:

Can anyone help me diagnose, por favor? The left channel went out. No noise, no crackling, no individual channel fuse to replace..just the single fuse which is good/the right channel works fine. When I use headphones..same deal.

I opened everything up but the pre-amp to look for individual channel fuse or charred looking parts or broken connection...saw no obvious problems.

i was told that one of the amp modules at the bottom of the cab is probably blown. I believe CAE has these for $150 w/ trade-in of old part. If i do that i wanna be sure tho. I guess I'll switch the amp module hook-ups tonight to see if it kicks in the left channel and takes out the right, to reference.

if it is the left amp module, can't i just solder in the part that's broken and not have to replace the whole module?

God (or Satan) bless you all for your feedback. This forum rocks!

Love,
 Sack

Offline suitcase'81

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'74 Suitcase 88..Left Channel Out!? Arrrrgh!
« Reply #1 on: June 01, 2005, 04:15:47 PM »
I seem to have the same problem.
My right speakers are "dead"..
thought it was a fuse thing but
the fuse on the outside is ok.
Anymore fuses on the inside of the cabinet i could check?

let me know when you fix the problem
and tell me how you fixed it..

I'll do the same if i happen to get it working
before you do..
"All musicians are subconsciously mathematicians."

Offline Sack

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One Channel Out...
« Reply #2 on: June 01, 2005, 04:42:43 PM »
i've been talkin to different techs. Apparently the problem can be (in my case) a power amp module, one of two light bulbs housed under these little metal boxes in the pre-amp, the 4-pin cable, or an assortment of other thing-a-ma-jigs in the pre-amp. My ex got a later 70's suitcase and she had the 2 extra fuses in the cab, one of which was blown. i fixed that for her. Unfortunately mine is a '74 and doesn't have the fuses inside the cab. i was told if a power amp module (there are 2 inside the cab) goes out..u will hear a loud pop! i know the bulbs in my pre are good, and am pretty sure the 4-pin cable is good, but have yet to test it. I'm leaning towards it being one of the power amp modules, even tho i never heard the pop! but i'm bringing my cab and preamp to a very nice/helpful guy in the bay area named Matt Cunitz(Vintage Keys) in a few days. will keep u posted. Open ur cab and check for the 2 fuses..great & cheap place to start...

Offline suitcase'81

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'74 Suitcase 88..Left Channel Out!? Arrrrgh!
« Reply #3 on: June 01, 2005, 04:48:54 PM »
I've got a suitcase from'81,
so I probably have those extra fuses you mentioned..
they are on the inside of the cabinet?
(the one on the outside below the power switch is OK)
wich side of speakercabinet should i unscrew of for easy acces?
(player-side or audience-side?)
and where to look?

Thanks a million!
"All musicians are subconsciously mathematicians."

Offline Sack

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'81 Fuses
« Reply #4 on: June 01, 2005, 04:56:47 PM »
..open the audience side. If I remember correctly, my ex's was a '79 and had them quite visibly exposed near the bottom of the main power amp mambojamba... Be careful tho..when i open my cab, the speaker wires to the 2 speakers on my grill are very short. i can barely reach in to unplug the slider-guys from the speaker cones.

Offline suitcase'81

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getting there
« Reply #5 on: June 01, 2005, 05:03:00 PM »
Thanks very much
Iwas already unscrewing the audience-side
(seemed much easier)
Have all bolts out, but the grillcloth covered thingy that holds the speakers won't come out..
should i use accesive force?  (probably not!)
there's nothing to hold on to to pull it out..
try to use my screw driver as a wedge but that's only damaging the wood
(not so good!)

now what?

Thanks
"All musicians are subconsciously mathematicians."

Offline Sack

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grill
« Reply #6 on: June 01, 2005, 05:07:45 PM »
..yeah, i use a butter knife for mine gently coaxing/prying it along the edges. it's always very tight, like a fine virgin. When it does pop out tho, be careful once again of the amount of slack coming from the speakers/wires from the speakers in the grill.

Offline suitcase'81

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'74 Suitcase 88..Left Channel Out!? Arrrrgh!
« Reply #7 on: June 01, 2005, 05:12:34 PM »
ok,

thanks for the hints and tips.
Hope the fuse is the problem,
otherwise i had fun prying her open...

Thanks again

and again and again
"All musicians are subconsciously mathematicians."

Offline suitcase'81

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I did it!
« Reply #8 on: June 01, 2005, 05:48:23 PM »
I got in!

I had "miles" of wires left.
I could almost set the grill and speakers in the other room..
But,  better safe than sorry.
And Yes there was a busted fuse,
so I hope replacing this one will fix all my problems.
If not, I'm one step further in the right direction.

Thanks for all your help..
Lifesaver..

I hope it was as good for you as it was for me .. haha
"All musicians are subconsciously mathematicians."

Offline suitcase'81

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Eureka!
« Reply #9 on: June 02, 2005, 07:59:54 AM »
Changed the fuse today.
That did the trick.
I can now enjoy in stereo again..

couldn't have done it without you.
Thank you very much.

Good luck with yours!
"All musicians are subconsciously mathematicians."

Offline Sack

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The final Solution....
« Reply #10 on: June 13, 2005, 01:24:14 PM »
We replaced a couple capacitors on the power amp module in question, and re-inforced the cold solder joints on the main lines to that amp module's circuit board(to be sure). it works now, kinda. we are thinking it was the caps..most likely.

however after a day of beauty, that channel now has a mild overdive ...arghhhh, again. will have it looked at again. i suspect replacing the caps prob caused a chain-reaction and half-fried some other cap or resistor-dealy on the amp-module. will let ya'll know what's up, when i do, if u care to, :roll: ...know.

Offline suitcase'81

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'74 Suitcase 88..Left Channel Out!? Arrrrgh!
« Reply #11 on: June 14, 2005, 06:46:27 AM »
I hope you get this frustrating problem fixed real soon,
so you can enjoy your rhodes in full working order again..
Good luck!
I'd like to hear what the prob was when you get it fixed..
Keep me posted..
"All musicians are subconsciously mathematicians."