Posted to sci.electronics.repair
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Tektronix 2445, No EHT , oscillator board 'failed' common ?
Graham wrote in
oups.com:
Found one fault, that was the soldered joint , center pin of the
switching transistor had failed , re made that and the oscillator
started running
Supply current 1.3 Amps , test wavefoem voltages all low , approx
50 % , sine waves clipped.
Tried disconnecting tube anode connector after running, tube produced
about 4 mm spark to earth.
Removed , two , connections from tags , rear of transformer to 'eht'
module ,
Supply current reduced to 450 mA . waveforms 'ok' re-connected
'upper' lead, (near qty 6 trim pots) slight increase supply current .
waveform's 'ok'
Re-connected 'lower' connection , supply current increrased to 1.3
Amps , wave forms low.
Not sure if lower connection is the anode or cathode (no pin numbers)
voltage source, either way, it looks like the 'eht block' has
failed ....
... who would have one of those ?
Tnx
Graham ..- Hide quoted text -
- Show quoted text -
Part number from manual
A9 VR 1830
152-0805-00
MF CODE 80009
HV MULT 20KV
Tnx - G ..
http://www.sphere.bc.ca/test/tek-parts/tekparts5.html
they have a used "as-is" one for $55 USD.
--
Jim Yanik
jyanik
at
kua.net
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