Your favorite game, and mine...”Name that weakest link”!

turnitup

No, the stereo won’t break the crystal...Oh CRAP!
I’ve been building a 1970’s man cave for while and have been looking for a color organ controller. Finally found/bought one, but it needs some “refreshing” after close to 50 years.

NEED SOME EXPERTISE!

This little thing is about as simple as they come, but I need some help with ID’ing what needs to be replaced. My gut is that the caps need to be replaced, but don’t really know what other “weak links” may exist. Hope I can get some educated AK consulting!

2EEABC36-EA0C-4FBD-97E2-60410E77664A.jpeg

D15C5FEE-9BC0-43C8-95D3-D713D31F08E8.jpeg

Thought I’d start with replacing the 7 capacitors. Can someone help me ID replacements through Parts Express? Here’s some close-ups. Thanks!

E9689060-EE5B-4835-8096-A41067E74ACA.jpeg AC38DCAA-A793-4F2D-9611-2A4BB46591F7.jpeg

88D7F9E5-D2FF-45C5-9CC7-50889EB90F93.jpeg
I’m familiar with replacing non-polarized crossover caps, but need a little coaching so I don’t burn this little guy up. Thanks in advance for the help.
 

Attachments

  • D7C5C715-A95D-4AFB-891B-1781A7D9E364.jpeg
    D7C5C715-A95D-4AFB-891B-1781A7D9E364.jpeg
    91.9 KB · Views: 11
Last edited:
It's been a very long time since I worked on any of these little toys, but I'm pretty sure the Triac/SCR in each channel is the most likely point of failure. You might also check for level control burnout.
 
Those film and what look like styrene caps are probably ok. I would agree on replacing the SCR's. A lot of the equipment used in my last job used them. Including speed control in the electric fork lifts. We kept plenty on hand.
 
Is the Psychodelic control center just an active tone control?

Oh no, it’s a wonderland of matching treble, mid and bass levels to pulsing lights. It’s tackiness and vintage lighting at its finest (or worst, depending on your take). I collect vintage 60s/70s psychedelic lights, and this is a must for my tacky collection. You adjust the pots to get optimum “light pulse reaction”.

Do the triac’s just die, or can they get weak? The controller works, just the mid and bass controllers (I.e. light reaction is really weak). My receiver went into protection mode at one point, so I’ve got some “short leakage” somewhere in the thing. Only happened when I turned the controls on the unit way up. Needless to say, its not getting hooked up again until it gets some work. Protection mode is not going to happen again!

Any specific triac’s that I need to get? I can post a picture if necessary, but they’re probably no longer made(?)
 
Any specific triac’s that I need to get? I can post a picture if necessary, but they’re probably no longer made(?)
The original part numbers are likely still available, or something closely equivalent. You don't want to make big changes here because the circuit is very simple and device gate sensitivity affects overall operation.
 
Thanks Mike, I’ll try to post a closeup of one of the Triac’s tomorrow. It looks to have a coil and a very small transformer too, connected right at the audio line-in (that the audio signal immediately runs through) before going any further into the device’s circuits. Could this be what triggered my receiver to temporarily go into protection mode? The devise looks like a very small transformer, but I could be wrong...
 
Researched a little bit and found that the audio signal directly from the receiver, most likely runs through an optoisolator (what I originally thought was a transformer) probably from the early 70’s. Wow, wonder if THIS is a replaceable part? Would guess this is where I’m having my “protection mode” issues with my receiver (on the back end). Could be causing a short that throws my receiver into protection? Chime in anyone if you have any advice, I’ll keep researching as I’d really like to get this little guy back up and running...
 
Thanks Mike, I’ll try to post a closeup of one of the Triac’s tomorrow. It looks to have a coil and a very small transformer too, connected right at the audio line-in (that the audio signal immediately runs through) before going any further into the device’s circuits. Could this be what triggered my receiver to temporarily go into protection mode? The devise looks like a very small transformer, but I could be wrong...
Yes it could. You need total isolation between the signal input and the controller. It may have backed up some AC voltage through the Ground wire in the cable. If you could photo. some detail around the input device, it would help. Show the wires as well.
 
Here’s a couple of pictures. The first is of the little transformer. All the transformer has written on it is “Japan”...which is not very helpful. The transformer’s 2 black wires go directly to each side of the audio inputs. The other side of the transformer (red/green wires) are soldered to the pots. One side direct solder to all 3 pots, and the other wire soldered to the opposite side of the pots, traveling through the 3 separate capacitors.

The 2nd and 3rd pictures are of the SCR’s/triac’s. 2 are the same part #, and the 3rd is a different part #, the IR 106 B1.
BCE402CC-01AD-4438-93D8-CF1A0A7FC94D.jpeg E224B3F1-DE84-4618-9CBC-1EC4A905AD76.jpeg BBBC07E6-829B-4FB5-9F83-8A8A30F4BB74.jpeg
 
Last edited:
Man, that's some ugly wiring.

The IR106B1 is a 4A 200V "sensitive gate" SCR. It can be replaced by NTE5455, which is available for a bit more than a buck from Newark and Allied. The other two GE devices are probably electrically identical. Keep in mind that we're all just guessing about what's wrong with this puppy...
 
Yeah, it’s a REALLY rough wiring job. Must have been quota work with no inspection.

I think (due to my receiver going into protection mode) I need to replace the audio transformer that separates the audio input from the line voltage of the unit, but have no idea of its specs, for a replacement...

Maybe this? http://www.electronickitsbychaneyelectronics.com/prodinfo.asp?number=G13599B

Thanks for the advice
 
Last edited:
Sorry, but I don't recall anything useful about the audio isolation transformers typically used here. If I had to guess, I would probably suggest a 600-ohm 1:1 telephone modem isolation transformer. If yours doesn't look overheated, I would take it out of circuit and do an AC function test by driving the primary with a few volts at 60Hz from a tube heater transformer or something similar. It would be trivial to derive the turns ratio at the same time, assuming that it's functional, and that information might be useful to other folks. A higher frequency test signal (from an audio signal generator) would be better.
 
Last edited:
Need to back up a bit... what works and doesn't work in this circuit? Is it getting power? Be very careful working with this unit, looks very dangerous to work on, this could not be UL listed the way it's designed, better get out that isolation transformer and be very careful with probing.

I'd imagine the three channels are run in parallel, are all three channels dead?
 
It’s UL listed...by Undertaker’s Laboratory...

When I had it hooked up, it was partially working. The “treble” channel worked, and a light hooked to it worked as designed. The mid and bass channels seemed to be non-functioning, but when I turned the pots to their maximum, I was able to get them to work, but just barely (a very weak light response). When I turned the pots on the unit to their maximum is when my receiver (which I had hooked to the unit through one side of my speaker B) went into protection mode. At that point I shut everything down...end of testing. No damage to the receiver, I was lucky.

The unit does work, but 2 of the 3 channels are weak in their lighting response, AND, it seems to be shorting out on the audio IN side, or feeding power back to the receiver (one of the two), hence the receiver going in to protection mode. This led me to believe that the two capacitors feeding the mid and bass lines may be out of spec and needing to be replaced, as does the audio isolation transformer. Pure speculation based on my very unscientific testing. The unit has 7 capacitors, around 3 resisters, 3 triac’s/SCRs, 3 pots, a coil, and an audio isolation transformer...that’s it. Simple design, and of course, the bailing wire architecture and build (which of course is icing on the cake)!
 
Last edited:
Well, if the treble channel works, likely that transformer is working too unless it's somehow dropping low frequencies (which it normally does). Not sure how well ferrite cores will work if it's low frequencies that's being dropped, the laminated steel EI cores are probably better for low frequencies.

What are you using to drive the transformer? Not sure if it should be taking speaker or line-level output, almost seems it should be able to take line level output?

The connections in the device are abysmal, can't make heads or tails of the signal path in the device. Also the pieces of component leads flying out as antennas are confusing. As far as I can tell, it would seem that sensitive gate devices are needed for all three channels as there's really no amplification, other than probably the transformer increasing the voltage somewhat - I suspect it's not 1:1.

Definitely should see if the carbon composite resistors are still OK too and check if the pots are clean.
 
Maybe this would help?

http://www.freeinfosociety.com/electronics/schemview.php?id=1526

colororgan.gif
 
Last edited:
Thanks for all of the input guys, very thoughtful of you to chime in and help me problem solve this little beast. I appreciate the help.
 
Back
Top Bottom