Timer/Enlarger...delay with activating light

Dave@Toronto · Sep 5, 2021

Just adding on to this thread because it's been extremely helpful: I've completed this repair on my Dual Dichro S head, replacing the old VTL9B8 with a VTL5C3. I made no other changes. Seems to be working perfectly now and there's no longer a delay when switching on the light with a timer. The S model looks a little bit different than the pictures above but the repair was the same. I ordered the VTL 5C3 here for $5 plus shipping https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html . One thing to point out for anyone else doing this who may have only limited understanding of electronics like myself: The old and new opto-isolators both have a wide side and a narrow side (on one side the pins are closer together than on the other side). These correspond with eachother between the old and new part so that's pretty obvious. Wider pins to the wider spaced holes and narrow pins to the narrow spaced holes. However you also need to get the direction right. If you look at the schematic above where R14 connects to ISO 2, it is not connected to the side with a dot. That dot in the schematic corresponds with a plus symbol on the VTL5C3. So, R14 should be connected to the side without the dot. It will not work if it's backwards. Otherwise a fairly straightforward affair.

Thanks to everyone who's posted here over the years! I'm super happy to have been able to fix this because it's been driving me nuts.

mshchem · Sep 6, 2021

Dave@Toronto said:
Just adding on to this thread because it's been extremely helpful: I've completed this repair on my Dual Dichro S head, replacing the old VTL9B8 with a VTL5C3. I made no other changes. Seems to be working perfectly now and there's no longer a delay when switching on the light with a timer. The S model looks a little bit different than the pictures above but the repair was the same. I ordered the VTL 5C3 here for $5 plus shipping https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html . One thing to point out for anyone else doing this who may have only limited understanding of electronics like myself: The old and new opto-isolators both have a wide side and a narrow side (on one side the pins are closer together than on the other side). These correspond with eachother between the old and new part so that's pretty obvious. Wider pins to the wider spaced holes and narrow pins to the narrow spaced holes. However you also need to get the direction right. If you look at the schematic above where R14 connects to ISO 2, it is not connected to the side with a dot. That dot in the schematic corresponds with a plus symbol on the VTL5C3. So, R14 should be connected to the side without the dot. It will not work if it's backwards. Otherwise a fairly straightforward affair.

Thanks to everyone who's posted here over the years! I'm super happy to have been able to fix this because it's been driving me nuts.

That's great. I think I've done 3 different 45S heads. The delay was always corrected by changing the iso 2 can. The soldering is pretty straightforward as you've found.

Thomas S · Sep 6, 2021

Dave@Toronto said:
Just adding on to this thread because it's been extremely helpful: I've completed this repair on my Dual Dichro S head, replacing the old VTL9B8 with a VTL5C3. I made no other changes. Seems to be working perfectly now and there's no longer a delay when switching on the light with a timer. The S model looks a little bit different than the pictures above but the repair was the same. I ordered the VTL 5C3 here for $5 plus shipping https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html . One thing to point out for anyone else doing this who may have only limited understanding of electronics like myself: The old and new opto-isolators both have a wide side and a narrow side (on one side the pins are closer together than on the other side). These correspond with eachother between the old and new part so that's pretty obvious. Wider pins to the wider spaced holes and narrow pins to the narrow spaced holes. However you also need to get the direction right. If you look at the schematic above where R14 connects to ISO 2, it is not connected to the side with a dot. That dot in the schematic corresponds with a plus symbol on the VTL5C3. So, R14 should be connected to the side without the dot. It will not work if it's backwards. Otherwise a fairly straightforward affair.

Thanks to everyone who's posted here over the years! I'm super happy to have been able to fix this because it's been driving me nuts.

Thank you! I just ordered a couple of these to try! I replaced the neon bulb in the "tin can" iso-2 as a poster suggested earlier on in this thread. This seems to have worked pretty well. The only issue I'm having now is that when I first turn on the enlarger, it takes about 30 seconds after switching the light on before the light will actually turn on. However, after the initial warm up, it is immediate and works well. I just need to remember to do another very quick warm up before each exposure to get a well timed exposure. Much better than before. I'm wonder if this new part will fix this entirely?

Anybody know what iso-1 does? I've thought about replacing that too in case that might help my "warm up" issue. But I really have no idea.

btaylor · Sep 6, 2021

Dave@Toronto said:
Just adding on to this thread because it's been extremely helpful: I've completed this repair on my Dual Dichro S head, replacing the old VTL9B8 with a VTL5C3. I made no other changes. Seems to be working perfectly now and there's no longer a delay when switching on the light with a timer. The S model looks a little bit different than the pictures above but the repair was the same. I ordered the VTL 5C3 here for $5 plus shipping https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html . One thing to point out for anyone else doing this who may have only limited understanding of electronics like myself: The old and new opto-isolators both have a wide side and a narrow side (on one side the pins are closer together than on the other side). These correspond with eachother between the old and new part so that's pretty obvious. Wider pins to the wider spaced holes and narrow pins to the narrow spaced holes. However you also need to get the direction right. If you look at the schematic above where R14 connects to ISO 2, it is not connected to the side with a dot. That dot in the schematic corresponds with a plus symbol on the VTL5C3. So, R14 should be connected to the side without the dot. It will not work if it's backwards. Otherwise a fairly straightforward affair.

Thanks to everyone who's posted here over the years! I'm super happy to have been able to fix this because it's been driving me nuts.

Thank you for posting the link to a replacement! I meant to order a few from a previous post with an eBay link, but I did not get to it and now the item is gone. I ordered 3, which should keep me covered with spares. This is an invaluable thread for anyone who uses these heads.

Dave@Toronto · Sep 7, 2021

Thomas S said:
.... I'm wonder if this new part will fix this entirely?

Anybody know what iso-1 does? I've thought about replacing that too in case that might help my "warm up" issue. But I really have no idea.

I think it is definitely worth trying to replace the part altogether instead of continuing with a (30-40 year old?) modified part. Regarding ISO 1, I'm going to take a guess that it has to do with the white light switch 'paper saver' functionality, which stops the light from switching on when the color filters are disengaged. I could be wrong about that... either way, I've never read anyone mention an issue with that part.

btaylor said:
Thank you for posting the link to a replacement! I meant to order a few from a previous post with an eBay link, but I did not get to it and now the item is gone. I ordered 3, which should keep me covered with spares. This is an invaluable thread for anyone who uses these heads.

Glad to help! I also ordered a few out of instinct but hopefully will not be necessary to do this repair again.

mshchem · Sep 7, 2021

Dave@Toronto said:
I think it is definitely worth trying to replace the part altogether instead of continuing with a (30-40 year old?) modified part. Regarding ISO 1, I'm going to take a guess that it has to do with the white light switch 'paper saver' functionality, which stops the light from switching on when the color filters are disengaged. I could be wrong about that... either way, I've never read anyone mention an issue with that part.

Glad to help! I also ordered a few out of instinct but hopefully will not be necessary to do this repair again.

Iso 2 is your problem. I've fixed at least 3 (4 ?) This was always the issue. Fixed I never had another issue. Sometimes the cooling fan acts up, people would run these units continuously all day. These units work great for VC and color.
Best Mike

CMoore · Sep 7, 2021

mshchem said:
Iso 2 is your problem. I've fixed at least 3 (4 ?) This was always the issue. Fixed I never had another issue. Sometimes the cooling fan acts up, people would run these units continuously all day. These units work great for VC and color.
Best Mike

Did you do much color printing.? (i never have)
I am still several months away from my darkroom being complete.
But 12 months from now, i hope to get my feet wet with color.

mshchem · Sep 7, 2021

CMoore said:
Did you do much color printing.? (i never have)
I am still several months away from my darkroom being complete.
But 12 months from now, i hope to get my feet wet with color.

I've done quite a bit of color printing starting in the 1970's, did quite a bit of Cibachrome too. Strictly as a rabid hobbyist. Professional photographers work hard!
I'm still set up for printing everything (except slides) I love darkroom work.

Thomas S · Sep 7, 2021

Dave@Toronto said:
I think it is definitely worth trying to replace the part altogether instead of continuing with a (30-40 year old?) modified part. Regarding ISO 1, I'm going to take a guess that it has to do with the white light switch 'paper saver' functionality, which stops the light from switching on when the color filters are disengaged. I could be wrong about that... either way, I've never read anyone mention an issue with that part.

Good point! I will replace with the new part when it arrives a report back with the results.

mshchem said:
Iso 2 is your problem. I've fixed at least 3 (4 ?) This was always the issue. Fixed I never had another issue. Sometimes the cooling fan acts up, people would run these units continuously all day. These units work great for VC and color.
Best Mike

Good to know. Thanks!

CMoore · Sep 7, 2021

mshchem said:
I've done quite a bit of color printing starting in the 1970's, did quite a bit of Cibachrome too. Strictly as a rabid hobbyist. Professional photographers work hard!
I'm still set up for printing everything (except slides) I love darkroom work.

Sounds wonderful........and marvelous too.

mshchem · Sep 7, 2021

CMoore said:
Sounds wonderful........and marvelous too.

It's really quite easy especially with modern chemicals and papers. In many ways less frustrating than getting just the right black and white print.

CMoore · Sep 7, 2021

mshchem said:
It's really quite easy especially with modern chemicals and papers. In many ways less frustrating than getting just the right black and white print.

The first time i Read / Heard this, i was 100% skeptical.
But now, i have heard it so many times.............there MUST be some truth to it.
I guess i will find out in 12 months.

Sal Santamaura · Sep 8, 2021

CMoore said:
Sounds wonderful........and marvelous too.

Ah, so Moore's fake. Your real surname is Gershwin. Are you George or Ira?

Brian Rotsten · Sep 21, 2021

Another satisfied customer with a 45s. My board had a qc date of 1983 on it.

If anyone is interested, the inside of the can:

mshchem · Sep 22, 2021

Brian Rotsten said:
Another satisfied customer with a 45s. My board had a qc date of 1983 on it.

If anyone is interested, the inside of the can:

View attachment 285852

So that's cool. I still have a couple Vactrol cans I acquired decades ago as back ups. Is that after modification?

Brian Rotsten · Sep 22, 2021

mshchem said:
So that's cool. I still have a couple Vactrol cans I acquired decades ago as back ups. Is that after modification?

No, that's all original. I replaced it with a VTL5C.

mshchem · Sep 22, 2021

Brian Rotsten said:
No, that's all original. I replaced it with a VTL5C. View attachment 285856

Perfect!

Thomas S · Oct 9, 2021

Thomas S said:
Thank you! I just ordered a couple of these to try! I replaced the neon bulb in the "tin can" iso-2 as a poster suggested earlier on in this thread. This seems to have worked pretty well. The only issue I'm having now is that when I first turn on the enlarger, it takes about 30 seconds after switching the light on before the light will actually turn on. However, after the initial warm up, it is immediate and works well. I just need to remember to do another very quick warm up before each exposure to get a well timed exposure. Much better than before. I'm wonder if this new part will fix this entirely?

Anybody know what iso-1 does? I've thought about replacing that too in case that might help my "warm up" issue. But I really have no idea.

I just replaced my "fixed" iso-2 with VTL5C3 and ... it works amazingly!!! I'm so glad to have my enlarger working flawlessly! Very exciting. The picture from Brian Rotsten really helped me orient this correctly. Just make sure the tiny plus (the longer wire on the LED "nipple" side) on VTL5C3 is away from R14 (facing up in the perspective of Brian's picture) as indicated by Dave@Toronto. Thank you all so much!!!

far2canadian · May 5, 2023

Keeping this thread alive into 2023!
I've just ordered two VTL5C3 from https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html

What you're all describing is precisely my problem. I've only recently learned to solder, and have never soldered a circuit board. So here's to new challenges.

Guys! THANK YOU for the great support and problem solving. I'll post again when I've received the VCTL5C3 and have made the replacement!

Lee

mshchem · May 5, 2023

far2canadian said:
Keeping this thread alive into 2023!
I've just ordered two VTL5C3 from https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html

What you're all describing is precisely my problem. I've only recently learned to solder, and have never soldered a circuit board. So here's to new challenges.

Guys! THANK YOU for the great support and problem solving. I'll post again when I've received the VCTL5C3 and have made the replacement!

Lee

I have replaced the iso on several of these heads, always solved the delay problem. IIRC there's 4 pins that hold the iso to the board. If I can solder it anyone can

CMoore · May 5, 2023

far2canadian said:
Keeping this thread alive into 2023!
I've just ordered two VTL5C3 from https://store.synthrotek.com/VTL5C3-Vactrol-Optocoupler_p_792.html

What you're all describing is precisely my problem. I've only recently learned to solder, and have never soldered a circuit board. So here's to new challenges.

Guys! THANK YOU for the great support and problem solving. I'll post again when I've received the VCTL5C3 and have made the replacement!

Lee

Generally speaking, PCB were hardier than what you would see today, but the same caution still applies.
I have done two of these but have forgotten what they look like as far as traces or turrets or eyelets.
If traces, get on and off as quick as you can... when you de-solder... with as little heat as possible.
The junk they call solder today, with no lead, takes a lot more heat. It is worth buying "real solder" just for the heat application alone.
Good Luck

far2canadian · May 12, 2023

Hey guys,

I got my VTL5C3 yesterday and am looking forward to replacing the Vactrol / tin can. Aside from the hesitations of never having soldered a PCB before (I'll get over it), I have a question about arrangement.

Looking at the diagram in the thread:

Comparing it to the photo of an upfitted board above:

And Dave@Toronto's description:
"The old and new opto-isolators both have a wide side and a narrow side (on one side the pins are closer together than on the other side). These correspond with eachother between the old and new part so that's pretty obvious. Wider pins to the wider spaced holes and narrow pins to the narrow spaced holes. However you also need to get the direction right. If you look at the schematic above where R14 connects to ISO 2, it is not connected to the side with a dot. That dot in the schematic corresponds with a plus symbol on the VTL5C3. So, R14 should be connected to the side without the dot."

Can I assume that my VTL5C3 needs to be flipped (in the photo below) so that the + symbol (to the right of "LED") is oriented toward the left of my PCB? I'd flip it to show what I THINK is the correct orientation in the photo, but there's no printing / polarity marking on the other side. So, is the + symbol supposed to be opposite the resistor in R14?

This diagram of the VLT5C3 seems to suggest that's correct - that the positive lead of the diode should be on the side away from R14:

Brian Rotsten · May 12, 2023

It’s been a couple of years and I cannot remember any specifics, but I do have another picture with a slightly different angle that shows where I marked the + lead on my board.

far2canadian · May 13, 2023

Ah perfect. Thank you!

far2canadian · May 16, 2023

I've installed the VTL5C3 and delay problem solved!

Timer/Enlarger...delay with activating light

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