Q about Tektronix 2220


I have a Tektronix 2220 with some startup problems. The power supply is not able to get the scope up and running, but if i disconnect +5V and +8,6V it works and after startup I can connect +5V and +8,6V and get the storage to work. I have checked and replaced a lot of capacitors but I'm not able to locate the fault.

Can somebody tell me how much current the different voltage lines draws in the unit?





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Reply to
Peter Andersen
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Peter Andersen sez:

There is a Google Group dedicated to Tek scopes and their repair.

E-mail the owner: TekScopes-owner at Yahoo or Go to Yahoo Groups and search for "TekScopes" and join that way.

The group has lots of experience and will probably be able to help you with the problem.

Good luck,

John English
Reply to
John E.

The service manual for the scope has a procedure how to check the LV supply. AFAIR there is info about the resistance you can measure at the varios voltage labeld testpoint on the printed circuit board. of course, scope is power of during these. The fault you describe I had in two similar Tek scopes, cure was both times to change the inverter transistors in the LV switchmode supply (beta was too low, as far as I remember).

hth, Andreas

Reply to
Andreas Tekman

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