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Peter Wallage
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 09, 2005 - 07:07 am: | 
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Hi Glen,
You obviously know your way around under the top of an A1. I wonder if you have come across the problem I have with one of mine. It eats batteries. A new battery lasts about four days, whether I use the camera a lot or not much. I've heard that it's a not-unknown problem, and wondered if you know what component is causing it and how to cure it. Could it be some sort of capacitor leak?
Thanks,
Peter |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 09, 2005 - 09:13 am: |
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Peter,Yes not unknown but off hand I cannot say what causes it.Good news is I have a load of original Canon service notes. I mean notes hand written Japanese!A friendly translator has transcribed a great deal and I am sure that this rings a bell, because battery drain (test?) is mentioned.Will have a search tomorrow and contact you.One thing what is the serial nos? as there are 4 distinct circuit diagrams/electronic mods. Glenn |
Ed
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 10, 2005 - 04:51 pm: |
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have found on a couple of ocassions, that the batttery test switch was bad. Remove the wire from it solved the problem.
Good luck |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 10, 2005 - 06:16 pm: |
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Peter,Some questions.This problem has suddenly appeared I take it?If problem arose after top removal, Ed's findings very possible.If view finder information not switched on, when pulling the top the contacts can get scrambled and short across test contacts which are in same group.Does camera function completely correctly apart from this annoying drain? Are all the slow speeds accurate-1/2 sec and longer?The drain occurs when the camera is switched and locked off? With it locked off press battery test button-LED should show no sign of illuminating.The aforementioned Canon notes make a great deal of the individual SR44 cells in the battery being upto spec.This is in the section on what appears to be abnormal battery behavior.As the majority of section is pages of scope traces I did not have my Japanese friend translate in detail,just para headings with comments similar to questions above-have now sent her the section for comments.Glenn |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 11, 2005 - 10:32 am: |
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Peter,Well here goes;
1,If the drain occurs with Main Switch in L position then problem is a high resistance short in either a flexi lead or a length wire that is trapped or rubbed.But if A1 is an early one then the actuating magnets were fed by a direct +ve from main switch,so cannot tell you what colour wire to check without serial and then it is 'ify'.
The following can also contribute to the above.
2,If drain is occuring when switched on then you can have two areas of concern,electronic or mechanical.Two switches give problems-Preview switch and battery test switch.the problems arise not only from the contacts being damaged, but from the insulators getting dirty.The insulators should be cleaned.In the case of the battery check switch the screw holding the contact and the insulators may have to be slightly loosened also.For a reason I cannot find, taking the test switch out of the circuit is not recommended, but as Ed says it does work.Might be to do with the way the +ve routes on some models.Electronics is more complicated.The battery current is first sent through a transistor and the current from it's collector is the supply that works the camera,except as mentioned in 1.This transistor may be 'leaking' or there may be a high resistance short to ground between it's base and the meter switch on the shutter button.If the oscillator interface IC breaks down this can also give the same problems.
So firstly give all the switch insulators a good clean.If you have a DVM micro ammeter connect in series with battery.If reading is less than 2 micro-amps then you done it.If greater than 2 micro-amps then check voltage on release magnet terminals.If reading less than a few millivolts the the osc/int IC could be the culprit.If it is more than a few millivolts then it is the aforementioned transistor.I have replaced the transistor but always swap the whole flexi for anything like an IC,but I am lucky as I have collected a number of good flexi's over the years. |
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