tektronix 2235 , blown switchmode

[john]

Hi All!

I have an old 2235 'scope which has died on me.
It looks like the resistor R909 and Q908 are fried . It also looks like
the IRF820 ( on heatsink) is blown.
Can anyone help with an excerpt from a service manual ( diag) or part
numbers/values ?

Does this happen often with these babies ?

Regards

John

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[TekMan]

john <john@agent-j.com> wrote in message news:<opsa7ax1pn0tb1i5@funkmeister.agent-j.com>...

Hi All!

I have an old 2235 'scope which has died on me.
It looks like the resistor R909 and Q908 are fried . It also looks like
the IRF820 ( on heatsink) is blown.
Can anyone help with an excerpt from a service manual ( diag) or part
numbers/values ?

Does this happen often with these babies ?

Regards

John

Hi John,

to answer your question:

1. the 2235 (and 2215/2215A etc.) are to my experience very reliable
scope, do there job well and keep accuracy well. good workhorses.

2. If they fail because of a fried power supply, the parts mentioned
above and in the other postings of this thread are 99,999% the cause.

Pls. do a google search for this topic, it is covered very often.
The component values are already mentioned in the other postings. If
you are in europe, consider also a BUZ80 (now something like BUK..-800
, AFAIK) from Siemens as a good replacement for the FET.

hth,
Andreas