Old Capacitors value

MrChips

Joined Oct 2, 2009
34,812
No. Don't start a new thread.
I suggest that you stick to one problem at a time. As far as I can tell from the photos you have posted so far, your oscilloscope appears to be working reasonably well. Pick one problem that you consider top on the priority list and focus on that problem.
 

Thread Starter

ren1976

Joined Oct 3, 2012
13
Now, replaced the ca3046 with new one the beam is more bright, so i've to regulate it, the intensified area for delay turns on , too bright but i think that tere is a way to regulate it.
The focus problem on channel ha , is still there but..it's quite strange… looks like a probe problem: when i touch the wire it decrease to normal. The strange is that is major it's only for channel A. The same probe on the B generate less interference. I still not investigate it, as you suggest a problem a time. Yesterday i focused on chop mode problem…When i turn it on , channel B and than B become very blurry, if i turn on trigger , also trigger was blurry. In mode Alt, A,B,A+B,A-B, Inv, were good. Only chop mode was blurry.I found that if i left the scope turned off for some minutes , when i turn on directly in chop mode , the beam is normal and become unreadable after 30-50 seconds.So i suppose a termal problem of some component. I checked the temperature of everyone but no one overheats. The only two with little high temperature were A3 Q17 and Q18 (+12Filter and -12Filter of the circuit) both arounf 50°c . To make a reverse test this moarning i used a hot gun (set to non destructive temperature) to warmup components and see if the problem starts directly. So, Q17, no problem, when i tried first time on Q18, the scope starts blurry. Turned off, i waited some minutes and turned on again with clear sharp line. Hot gun again...clear line...again ...clear line... so it's not q18...Than i spent 3hr to test every component on A3...always clear line, works perfectly...so...turned scope on ...and left it turned on for half an hour….no problem….very strange. So, i don't know what happend but now the problem is solved. I can't imagine that a 70-80° c applied to the component could repair some invisible cracked joint...So now the scope is working very well,except for UNCAL led of channel A that is broken,but i don't want to disassembly A3 just for a led without another really good reason . I have not done any fine calibration becouse i've not a function generator (next buy) but as i can see comparing the Hameg it is already good calibrated.I'll wait for new 100mhz probes and meanwhile i'll rebuilt broken knobs and some cosmetic things. For now i thanks everybady for suggestion and precious help .Chop.jpeg
a video
https://drive.google.com/file/d/1ovTLd5yy0EprazTnAuogTOJNFgq_fYdJ/view?usp=sharing

and ...
the home made component test ...
component tester.jpeg
 
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