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Hi jeff Responds to stress.....dry joint?...something never soldered?....pcb crack?...resistor cracked?...As you can tell I'm not an expert but pressure related
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faults seem to fall under such headings rather than complex circuit issues. My Regards -----Original Message-----
From: Jeff Urban Sent: Saturday, November 3, 2018 4:46 PM To: [email protected] Subject: Re: [TekScopes] Tek 465 "B" Sweep Has another problem. The front end of channel 1, the lower V/div. settings result in a distorted square wave, and I mean distorted. Sometimes overpeaked and sometimes underpeaked. I have determined it must be around the X100 attenuator, but not the attenuator itself. the problem occurs when it is supposed to be bypassed. I disturbed the contacts a bit to no avail but putting stress on the body of the attenuator assembly affects it, makes the problem come and go. Some deoxit will be here tomorow but I doubt that is going to fix it. All other ranges are stable, why only the ones that need that doodad bypassed ? why not all of them. Plus being gold plated they never corrode so the only thing that can happen to them is shit condensing from the atmosphere or something like that. I looked it over and RTFMed the R & R of that assembly and it is typical, doable but kinda like working on as Tektronix scope, know what I mean ? I figure maybe the case settled or whatever and isn't letting the fingers seat on the contacts quite perfectly. It could also be solder connections but those are extremely rare in Teks as far as I've seen. I wonder if maybe the bearings or whatever holds the drum might be out of kilter. I figure I'll wait until the deoxit is here and clean it anyway while it is all apart. But all in all I am glad the sweep problem is fixed. I could just run it on one channel if necessary. I dunno, it is better than any of my other scopes right now. Maybe I'll sell a couple of beaters and pay for this one. Actually I want my 7603 back that I sold when I gave up on it, and I think I'll have it when I get my cohort's 7834 fixed. They both have regulation problems and they are coming up soon. I am getting back into it, and liking it. Actually being able to see helps quite a bit. Remember I fried that 7603 because I couldn't see worth a shit. I got plugs reversed and dumped the +130 into the +5, it wiped out the H switching IC but I had one luckily. Eventually I got it running, when I no longer owned it. I LIKE that 7603, I don't care it weighs as much as piano. (well a digital one anyway...) I'll keep you posted, and am looking for ideas as usual. I'll have pictures and whenever the gallery gets really organized, pictures like that can become part of information on how to work on those things for future reference. Not really a tutorial but something like it. I'll bring all my Tek business here. -- Jack |
