Jean-Paul,
One comment. The 7904/7904A has a 500 MHz bandwidth. The 7834 has a 400 MHz bandwidth. The 067-0587-02 standardizer has a 1 GHz bandwidth, and the 067-0587-01 standardizer has a 500 MHz bandwidth and may be used in both the 7904 and 7834, and it is somewhat less rare and expensive than the 067-0587-02 standardizer.
DaveD
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On Jan 8, 2022, at 04:37, Jean-Paul <jonpaul@...> wrote:
?Don, bonjour monsieur
7904 is a great scope, my workhorse for 7000 plug-ins.
0/ please DO NOT use any cleaning on plug-ins attenuators before you read the precautions and proceedures, eg 7A29 has elastomeric membrane contacts and polysolfone PCB attenuators.
1/ In PSU, check voltages and ripple, may need recapping,
2/ A frequent source of problems and intermittents are the single row "harmonica" flat cable connectors that mate to pins on the PCBs, after decades the plastic becomes brittle and crumbles, so the contacts springs loose tension.
3/The square Bourns "mod posts" can be cleaned by just spraying the shaft and sides, oftentimes enough cleaner leaks inside to fix scratchy control without disassembly.
4/Finally the main backplane (and perhaps other boards) have axial tantalum caps which sometimes fail open r shorted.
5/ Exchange of CRT will require complete recalibration, so have the service manual and requiert equipment on hand. Note the (rare) TEK reccomended calibration plug-in, 067-0587-02 Signal standardizer. I wouldn't swap CRT if it can be avoided. Take all safety precautions in handling a CRT! DANGER OF IMPLOSION!
hope that this is of interest
Bon courage et Bon chance
Jon
