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Old 22nd February 2009, 01:58 AM   #51
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Well, then I shall pass on the reel to reel deck devices. If you have a particular project for them, I will not break a pair, because I can really use any deck to get parts. My thing is "cannibalizing" discarded equipment, stuff that's too far gone to be restored, and using it to make something similar, just because I can. Or I think I can..

Anyhow, take a look at page 6-3 of the service manual of your 654a. Look at reference designator DSV1, the manufacturer's part number is CLM5012. I found nothing on the net for this part. I dd however find CLM6000, but that tells us nothing about the 5012. If one can ssume they are closely related, then the specs of the CLM6000 could be the same for the CLM5012. anyway, I'm still wondering how you can determine a good replacement for this. If only someone had a Vactrol (I think they became clairex) catalog, we would have some specs...

euh, help, anyone?

tu parles d'un nom "vactrol"... Pas ben ben de québécois su'l site hein!? non hein.. pas un qui lis ça hein sinon i pourrait peut-être nous donner un signe de vie?
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Old 22nd February 2009, 04:25 PM   #52
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Oh, dont pass on the reel to reels!! All I would be doing with them right now is scavenging the trannys and tubes and what not, but all the mechanical is just sitting there. I do have better ones, but they are all in Alberta with my parents.

Back to the optoisolator...I cant disect this one to find out if its a LDR and LED, or if it is actually a lamp (the difference being that LED only conducts (for majority carriers) in one direction.
Looking at the schematic I think if it IS an LED/LDR I could hook the cathode end to circuit common, and anode to the rest of the ampltude control integrator.

Ill try to bias the device I removed (if its able to..cant test it without it being on. haha. ) and see whats what, but I think it is a lamp with a burned filament.
I couldnt find any info on the VACTEC 8603, but I did find that small bear electronics sells the Clairex CLM6000 (what you mentioned) for 7.95 (ouch) but yes, like you said..all the phasor guys still use these, so I should be able to find one

Then thats the next question..how much is this device allowed to deviate and still work in the circuit?? I measured 500 ohms (about) for the sinewave to clear up, and these are 500ohm Ron, so possibly just plop one in and see I guess

I have a Roland Phase 5 (guitar pedal) and I do recall it having an optoisolator like this one..Ill open it up and see. They are almost the same vintage. haha

Also, the effect makers rave about.. VTL5C3, and...NSL32 but I havent researched them yet.

Gotta love/hate HP and thier resistive-lamp-feedback circuits!! haha
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Old 22nd February 2009, 05:11 PM   #53
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Well, I don't need the parts right away to be honest, like I said I got the "other" big project to finish first!

you know instead of putting a fixed 500 ohm resistor, why don't you just put in a linear 2Kohm variable resistor? Or somewhere around 2K, close enough to 500 ohms but will give you enough room upwards to clear it up. I don't get the impression that this particular optocoupler goes to very high resistance. Personnally I think this was a custom-made part for HP. Have you tried sphere electronics in BC? ( http://www.sphere.bc.ca/ ) Maybe they have a spare part for this, altough, you're likely to pay a high price, but if they have it it will be the exact part from HP.

Your idea of dissecting the optoresistor is good, that's what I would do. I am certain it's an incandescent lightbulb in there, and it's burnt. If you can find "wheat-germ" light bulb, in either a hobby store, or any electronics store, you might be able to make a drop-in replacement! That would be super. But you have to able to open up the case in a way that permits reassembly you know... lol!

good luck, or good work!
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