Recently Failed Timer/PowerSupply for Chromega II

[robert_starbuck1]

Yesterday my Chromegatrol (Cat#412-040) failed to turn off the lamp at the end

of its timed interval and has since kept the lamp ON despite everything I have

tried. (Of course, the master POWER switch still turns everything off.) My

questions are: (1) Is this a problem common enough that others have experienced

it and have any user-servicing suggestions as to a solution? (2) What is the

cost of having Omega repair it - if they do any longer, if the fix will last,

if it is "worth it", etc.? (3) Would the use of a regular timer (eg a GraLab

300 or, my favorite, the 400!) introduce a problem as to cooling since the

Chromega II head's fan would not operate between exposures as with the

Chromegatrol?

Thanks!

[len_robertson]

Robert - You may find the answers you need on the wonderful Omega enlarger forum:

http://www.classic-enlargers.com/cgi-bin/yabb/YaBB.pl?board=general

 

Len Robertson

[robert_starbuck1]

That is a WONDERFUL place...I'll check there! Thanks

[robert_starbuck1]

Communication with Harry was very helpful. I had discovered that I already had an Omega SUPER CHROMEGA DICHROIC Power Supply (Cat. No. 412-021); an Omega Solid State Precision Timer (Cat. No. 461-012); an Omega Solid State VOLTAGE STABILIZER (Cat. No. 404-841); and a non-Omega Linemaster "Treadlite" foot switch - all connected together from another Chromega. Not only did it all work in place of the Chromegatrol, but ANY standard enlarger timer will also work by routing its power through the 412-021 power supply. So I now have the option of using a GraLab unit if desired. Thanks.

[robert_starbuck1]

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[gone fishing]

Robert-

This happened to me recently and, after disconnecting the AC Line and removing the cover I found that the wiper-arm(s) on the decade switches were oxidized (probably from lack of "exercising" them by rotating through their positions). I used WD40 and a cotton swab to clean them (carefully - in order to prevent bending or twisting them) and the unit was restored to normal operation. Obviously I don't know if this is the case with your unit but the decade switches used in these units are susceptible to this type problem, particularly in humid environments. Hope this helps!

Joel Edmondson

[robert_starbuck1]

...gonna try that...now where's my WD-40...? Thanks!

[robert_starbuck1]

Joel - How did you possibly access the contacts within the rotary switches? They appear entirely sealed against a multi-solder connection to the circuit board. Puzzled...Bob

[gone fishing]

Bob - On the unit I have the contacts, other than the point which is selected at the time, are exposed enough to allow access. I don't know whether there are differing units over the life of production but most rotary switches I have seen appear similar with the wiper arms rotating to make the circuit through the decades. Usually the stationary "spring-type" contacts on the fixed wafers are the culprits as the result of oxidation forming on the contact points and units which are frequently rotated through the ranges don't seem to have the problem... Joel

[Amanda B]

Hello! I know this is an old post, but I have multiple Chromegatrol timers with this problem (timer stopped working, they just stay on). I wonder if Joel or someone could possibly take a photo of the decade switches that they cleaned so I know what I'm looking for? I can wield WD-40 and a Q-tip, but I know nothing at all about electronics.

Thank you!

[john_shriver]

WD-40 is NOT suitable as a contact cleaner. There are specific electrical contact cleaners.

[Niels - NHSN]

Deoxit is often mentioned on vintage stereo forums.