No resistance between Black and red, on both. open circuit ?
tell me if these pictures work for you:
No resistance between Black and red, on both. open circuit ?
tell me if these pictures work for you:
Not sure where to go next. A few notes. I see 7 alterations to the circuit. 4 on the bottom and 3 diodes added in parallel to resistors.
The Relay is a 2 pole (under 2Adc) relay. Do you hear the relay click when you do something?
There are 4 adjustable resistors, white with slotted screws on top next to black connector. Is there a calibration proceedure that requires adjustment by the user? I'd guess not and that it was pre-adjusted since it was for a known lamp.
The 14-pin black parts with "ST" on them are quad opamps. Something generic probably, such as an LM324.
U5, in the corner, is a Motorola part ("M"), probably logic, and not fully utilized. Not all pins are connected. Probably an oscillator since there is X1 right there.
Can you read U6 part number? Wipe with a wet Qtip maybe. (actually, this won't matter, just curious).
I see no signs of heat or distress. Half of you circuit works. Both tubes are good. You can reassembly with transformers swapped to see that they are both okay. I don't understand the transformers or why the red/black are open, but they are the same.
I recently fixed a product sent to me. It was a 30-year-old timer. It had a bad capacitor in it. Shorted. It was not a large value cap, but a little one. I'm not worried about the dipped tantalums (such as C5 and C9), nor any of the blue ones, big or small. The little yellow ones are a concern, especially C9 and C14. Perhaps measure across these for a low value on your ohm meter. I'd try not to fold them down as they can be a bit brittle and you don't want to bugger up where the leads enter the yellow part.
Other than that, I got nothing until you have a schematic. I know you really want this to work. Troubleshooting like this is tedious.
I have a 8x10 Zone VI enlarger with a aging cold head and I am considering upgrading to a Heiland LED head. It is pricy but would last a lifetime and would be more versatile and reliable than the current fluorescent bulbs.
Ditto.Originally Posted by cuypers1807
Keith Pitman
Same here, except mine is a Beseler 810 (sort of) and I'm almost done with my LED head. Here's a couple very early pix of beginnings.
1st pic is 3 of 9 green LEDs lit.
2nd pic is 1 blue LED lit and diffusor material
3rd pic is placement of 18 LEDs
it's sentimental, as I explained before, and it's a nice challenge, no ?
I use a Heiland Led head on my Focomat V35 and a split grade head on my De Vere 504. Both are connected to the same Heiland Split grade unit.
It works perfectly and I know Leds are almost for life !
I bought some leds 35w for another project but I already thought to make an LED head for my huge Durst 1840.
How do you choose the colors green and blue, don't you have to respect a specific color temperature?
What power do you use?
Eric, do you think that if I sent you that head you could do something?
My only fear is to break one of the tubes during transport
Led like this ?
10w et 35w 36v
It is a good challenge, but until we have more info, I'm stuck.
I've never seen those LED modules before.
I buy the 3-up LED stars from LED supply. They are CREE. I bought the green and ROYAL BLUE. You need the royal blue at highest contrast so you don't 'leak' any into the green sensitive area. The plain blue LEDs are too close to the green spectrum. My power supply is 200W, which I now estimate to be about 4X too bright. We'll know soon.
If you use BLUE LEDs, be careful. They are very bright and your eye doesn't stop down as much as they should because it doesn't see that blue very well. Use sunglasses.
I'm sorry I can't work directly on your power supply. I have so many projects to finish and I have a damn disease that competes for my time and emotional energy. You seem to be doing pretty well. If you swap the known good transformer into the bad position and it works, then you'll know the xfmr is good. Having to find another of those could be a deal breaker unless there is a manufacturer's name on it. Then check those caps.
Maybe post a schematic request over at Photrio if you can't find one otherwise.
Best, EW
From your trouble shooting it appears that the "transformer" unit is bad. Since it's bad anyway maybe you can figure out how to open up that white case to see what's inside. Might be some replaceable components in there.
The minimal range of contrast was always my bugaboo with the Zone VI. I upgraded to an LPL machine for up to 4x5 and adapted a Kienzle head to the 810, never missed the ZVI "VC" head.
Sentimental isn't my thing anymore.
Posting Permissions
Reply With Quote
Bookmarks