TDS544 oscilloscope repair

[aalavi]

Hi Fellows,

I got my hand recently on a TDS544 oscilloscope. It powers up, fan blows but few random screens, and a persistent icon of a little clock on the black screen is all I see and nothing after. Could anyone point me to a post or discussion group that I can learn how to start with fixing such devices?

I opened it up and visually checked the boards for any sign of capacitor leakage or burn but everything seems quite clean. Here is what I see when turning it on:



Any hints, ideas would be most welcome!
Regads,
AA

[Fet]

I got my hand recently on a TDS544 oscilloscope.

anyone point me to a post or discussion group that I can learn how to start with fixing such devices?

Here ya go,,,,,,,,,,,

http://www1.tek.com/forum/viewtopic.php?f=5&t=5115

[djsb]

Try here

http://tech.groups.yahoo.com/group/TekScopes/?yguid=330951138

and look for sphere research in your country for spares/manuals (http://www.sphere.bc.ca/). Start with this

http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf


David

[nctnico]

First of all: you have to wait much longer. These scopes take very long to start. You can make the start-up time shorter by setting a dip-switch inside to skip the extended power up self tests. The fan may be a temperature controlled one so it may fluctuate a little bit.

Someone compiled a whole list of threads on the Tektronix forum:
http://www1.tek.com/forum/viewtopic.php?f=5&t=4886

You can download the 'TDS520B component service manual'. The TDS5xx, 6xx and 7xx scopes are very identical when it comes to the electronics. Leaky capacitors are not easy to spot. Under certain light angles you can see a grease spot around a capacitor. And the smell of cat-pee is also an indicator of leaky capacitors. In my experience scope from th early 90's have the leaky capacitor problem. Later models (from 1995) don't have this problem even if they have electrolytic capacitors. Its just a bad batch of capacitors.

[aalavi]

Thank you all!

I was wondering how long is long? I let it run for 10 mins last night and still the clock icon and nothing more.

I will read through the documents and yahoo group posts for a while and try few things. Then I will write back if I can fix something or if i have further question.

Regards
AA

[elliott]

First thing I'd do is go through and re-seat any cables and socketed chips.

[nctnico]

You are better of following the service manual. IIRC there are several dip switch settings which can help to diagnose problems. There is also an LED display inside which shows an indication where the scope stops during boot.

[FenderBender]

Those TDS scopes are just a pain in the arse sometimes.