Eko Tiger organ repair question

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efinque

Well-known member
Joined
Jan 3, 2018
Messages
350
Hello,

I recently acquired an Eko Tiger vintage electric organ from the 70's. It had a broken fuse but replacing it made the unit work for a while, after that it let some smoke out and now there's nothing but a loud hum coming from the speakers. The lamp also burnt but the PCBs seem fine so I think it might be the transformer.

Does anyone have any experience repairing these?

Thanks in advance,

-ef

EDIT : for the record I've once fixed a vintage Walton organ but all it had was a broken power cord, this may require some additional work which is why I'm asking

EDIT 2 : and it's not that the sound is particularly great, it's in fact very thin but it looks very nice and could be used in some recordings for a vintage sound but I don't have much time or resources to exclusively focus on fixing it

EDIT 3 : I already tried powering it with a wall wart, the hum reduced a bit but no sound from the keys (the hum is present in the hp/line out too).. there's a small component (in the PSU) underneath a huge capacitor that looks like a diode which could be damaged and the hum could be a short in the speaker PSU (it has 2 power supplies.. design-wise it's fully modular, the oscillators, tone etc) I'll upload some close shots of the internals once I get around to it. The PSU seems to accept a wide variety of voltages by changing the fuse position which could've been my mistake, the thing eats 0,5A fuses but I put a 0,63A in which could've fried the trafo, I also tried a number of other fuses with no luck

EDIT 4 : I've been also looking for suitable Hammond transformers but they're pricey, somewhere around 100e and upwards. This unit is from '72, model n. 3000

EDIT 5 :
IMG_20180716_225611.jpg
Here's the part I believe is broken (behind the vertical capacitor)
 
Popping fuses is a problem.
You need to isolate what is causing the fuses to blow.  I suspect off hand the rectifier/s.  But that is just a guess. If you know the output of the psu can measure it with dmm.

I have had in the past fault my transformers cause this and I would be easy to check for shorts.  Just disconnect the secondaries. Make sure they don't touch anything and power it up. If the fuse stays then you are ok.  If the fuse blows then you either have a short in the power transformer or you accidentally touched the leads on something.    If the fuse stays then disconnect the psu,  reconnect the secondaries and try again.  See if you can get fuse to pop and note when it happens
 
pucho812 said:
Popping fuses is a problem.
You need to isolate what is causing the fuses to blow.  I suspect off hand the rectifier/s.  But that is just a guess. If you know the output of the psu can measure it with dmm.

Thanks.

One idea was to turn it into a mixer frame (it's wood, tolex and faux wooden looking cover with sturdy metal stand ie. very heavy construction-wise)

EDIT : Here's a few more pics

IMG_20180716_164608.jpg


IMG_20180716_164835.jpg
 
As said, it could be a shorted rectifier (unplug it and test each diode with a DMM in diode mode - forward should be around 500 or 600,  reverse should be open.

Next I would check for a bad filter capacitor, though it may be easier/quicker to just replace all the power supply electrolytics with new ones. You might want to redo the other electrolytics, but those would only make bad sound, not blow a fuse. You might even want to do this anyway, it might be a bad cap causing a rectifier to go AND the fuse to blow.

I suppose it could be the transformer, but I think the others are more likely.
 
of all the things that could go wrong in a PSU the transformer is not the first or second thing i would think of, I put them way at the bottom of parts to check for failure.
 
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