Confusion on repairing my pca-060 color analyzer

[czygeorge]

I've had two of this model of analyzer(The last one works great and I gave it to my friend),And this time when I was calibrating the one I keep for use,when I change to m and y channel the needle just stay in the left(even with largest aperture)

I think it's because those filters in the probe are dirty,and finally I found this piece of plastic filter which cover the sensor.

I took it off and, y channel still stay on the left,And as always they only move when I put a flashlight on them.

Anyone knows what this filter do?and is there any possibility to repair it or just put it in the trash bin

Really appreciate for help and any advice

 

[koraks]

Anyone knows what this filter do?

It looks like the kind of color filter that's common on RGB photodiodes. At least that's where I encountered them. It's the kind of part that is of crucial importance to maintaining proper tracking between the channels, as the calibration range is likely more limited than the much bigger influence of a filter like this, which compensates for the inherent sensitivity difference between differently doped photodiodes.

Btw, it's probably not plastic, but actual glass and might be quite brittle as well.

You'll have to put it back where it came from, ensuring it will remain in place, and without using a glue between the filter and the sensor that degrades either over time or shifts in color (many transparent glues tend to yellow, which would be problematic here).

 

[czygeorge]

I've had two of this model of analyzer(The last one works great and I gave it to my friend),And this time when I was calibrating the one I keep for use,when I change to m and y channel the needle just stay in the left(even with largest aperture)

I think it's because those filters in the probe are dirty,and finally I found this piece of plastic filter which cover the sensor.

I took it off and, y channel still stay on the left,And as always they only move when I put a flashlight on them.

Anyone knows what this filter do?and is there any possibility to repair it or just put it in the trash bin

Really appreciate for help and any advice

It looks like the kind of color filter that's common on RGB photodiodes. At least that's where I encountered them. It's the kind of part that is of crucial importance to maintaining proper tracking between the channels, as the calibration range is likely more limited than the much bigger influence of a filter like this, which compensates for the inherent sensitivity difference between differently doped photodiodes.

Btw, it's probably not plastic, but actual glass and might be quite brittle as well.

You'll have to put it back where it came from, ensuring it will remain in place, and without using a glue between the filter and the sensor that degrades either over time or shifts in color (many transparent glues p to yellow, which would be problematic here).

Thanks a lot KoraksNow I know what it is
Unfortunately t's full of haze now(which can't be wiped off,don't know why maybe due to the long time of using),and I think the only way to save it is to buy another instead

 

[koraks]

I don't think you'll ever be able to find an exact replacement of the photodiode used here as this is old equipment and the production life cycle of such parts is usually far shorter than the current age of this equipment. Besides, good luck finding a part number in the first place.

Sorry, there's not much you can do to salvage that one. Some things you can safely tinker with on equipment like this, other things you really need to steer clear of.

I fixed a Colorstar the other day that turned out to have a simple cable conductor break somewhere, resulting in behavior identical to your unit. Had I started messing with the actual diodes and the amplifier stages, it would have been FUBAR for sure. With stuff like this you need to have a basic idea of what you're doing if you don't want to mess it up.

Perhaps you can still sell or donate the unit for parts of repair to someone.

PS: even if you could locate a spare part (e.g. by ripping it from another identical unit) you'd be left with the calibration problem. I'm not sure how feasible it is to perform a factory calibration on these, given that the necessary information and calibration targets are (1) probably not public domain and (2) are likely lost forever in the many reorganizations and restructurings Philips has gone through over the past 4 decades.

 

[czygeorge]

I don't think you'll ever be able to find an exact replacement of the photodiode used here as this is old equipment and the production life cycle of such parts is usually far shorter than the current age of this equipment. Besides, good luck finding a part number in the first place.

Sorry, there's not much you can do to salvage that one. Some things you can safely tinker with on equipment like this, other things you really need to steer clear of.

I fixed a Colorstar the other day that turned out to have a simple cable conductor break somewhere, resulting in behavior identical to your unit. Had I started messing with the actual diodes and the amplifier stages, it would have been FUBAR for sure. With stuff like this you need to have a basic idea of what you're doing if you don't want to mess it up.

Perhaps you can still sell or donate the unit for parts of repair to someone.

PS: even if you could locate a spare part (e.g. by ripping it from another identical unit) you'd be left with the calibration problem. I'm not sure how feasible it is to perform a factory calibration on these, given that the necessary information and calibration targets are (1) probably not public domain and (2) are likely lost forever in the many reorganizations and restructurings Philips has gone through over the past 4 decades.

Ok thanks a lot korak!I think it's time to stop having the hope to save it too
Sure if it was me I want touch the probe of color star too(And also I had a friend here also met this problem-broken wire of colorstar and he fixed it,I thought mine was the same problem too until one day i clean the record part with circuit cleaner and it worked perfect again)

 

[koraks]

circuit cleaner

I would not take that stuff near this kind of equipment. The opamp circuitry is extremely sensitive to fouling that may be left by the cleaner and the muck it dissolves.

 

[czygeorge]

I would not take that stuff near this kind of equipment. The opamp circuitry is extremely sensitive to fouling that may be left by the cleaner and the muck it dissolves.

So how could you clean the circuit
I once used a chinese cleaner to my timet and it melted the plastic...So i changed back to an american one which won't

 

[ic-racer]

I'd look for loose or corroded connectors and cold solder joints.

 

[koraks]

So how could you clean the circuit

Depends on the nature of the circuit, the components and the dirt/fouling that needs to be removed. There's no one-size fits all solution, but in general I try to remove as much muck as possible mechanically and then if additional treatment is required, it depends on the factors mentioned. In any case, what I never do is just douse a PCB in some kind of cleaner and call it good. That just redistributes dirt all over the place and potentially adds some new residue.

 

[czygeorge]

I'd look for loose or corroded connectors and cold solder joints.

Thanks ir
I'm not a good circuit repairer but found lot of this problem in old darkroom equipmentUnfortunately I never could find them

 

[czygeorge]

Depends on the nature of the circuit, the components and the dirt/fouling that needs to be removed. There's no one-size fits all solution, but in general I try to remove as much muck as possible mechanically and then if additional treatment is required, it depends on the factors mentioned. In any case, what I never do is just douse a PCB in some kind of cleaner and call it good. That just redistributes dirt all over the place and potentially adds some new residue.

Thanks again Koraks
Another problem i think is you know all the old components,those old capacity or sensors,I actually still afraid someday my jobo atl circuit board stop working