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  1. S

    Tek 2235 Power Supply Revisited

    Yeah, 40 years doing this myself. We're dinosaurs now. All the new gear is just swap boards, and throw away the old one. Ain't a whole heck of a lot of guys like us left, ....and when the old gear is gone, we'll be too.
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    HP/Agilent 3336B Synthesizer/Level Generator schematic

    I've got two manuals on this instrument, and I don't see any reference for your 'control board',... I'm wondering if this is some type of custom option. You might consider who you got the instrument from, and it might help you find out where to start looking for a schematic. Military...
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    Tek 2235 Power Supply Revisited

    I would've been screwed too. I didn't even KNOW they had some different military version of a 2235 (I have one, it's my main hobby scope). If you couldn't find the problem in the power supply itself, I'd be betting whoever worked on the scope last, made one too many mistakes, elsewhere in the...
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    HP serial number

    I checked some Tektronix manuals, and THEY have a list of countries of origin, tied to the serial number: B000000 Tektronix, Beaverton, Oregon 100000 Tektronix, Guernsey Ltd, Channel Islands 200000 Tektronix, United Kingdom 300000 Sony/Tektronix, Japan 700000 Textronix, Holland...
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    Tek 2235 Power Supply Revisited

    I've only got the one manual on this scope. I agree, you're going to need the manual for the military version you've got since it's different. Did you check with Tektronix, to see if you can get one from them? They may have a way for you to just get the schematic, without having to pay for a...
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    HP serial number

    I'm just not seeing it. I checked a dozen HP manuals. The only reference I saw was that the prefix of the serial number is the type of instrument, and the suffix is an actual serial number for it. Maybe you've got a particular class of instruments that this theory pertains to? You can find...
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    HP serial number

    40 years on HP gear, and I learned something new today. I'm told some HP manuals give a breakdown on your serial number code. It tells you the date of manufactor AND the location where the instrument was built. I don't know what it is, but I've got a room full of HP manuals, ...so I'm going...
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    Tek 2235 Power Supply Revisited

    I can see why you're frustrated, there's not much else left to check. I'd check Q938, Q939, Q944, Q946 & Q947 (Back to back resistances, for a short). If you can't find the problem, you're going to have to recheck those previous repairs you said somebody else already did. If I was you, I'd...
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    Tek 2235 Power Supply Revisited

    I'll look at the schematic again. But I'm telling you right now, I'd replace C906, whether you figure it tests good or not. I'll send another post after I recheck the schematic.
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    Tek 2235 Power Supply Revisited

    How's your C906 (75ufd cap), and that bridge configuration CR901 thru CR904? Did you check that? It's supplying your circuit that keeps frying. (And CR920 can screw you, if it's bad). TP940 should give you a good indication of the health of that circuit, Check Q908, if it doesn't look good.
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    HP serial number

    Hmmmm.... never heard that you can tell date of mfgr FROM a serial number by itself. I know manuals often refer to revision changes from increasing serial numbers, but I don't think you can actually tell the year of manufacture from the serial number, as if it was coded with the year in it...
  12. S

    AT90CAN128-16AU

    That email removed was a place called gulf distributors, in Florida.
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    AT90CAN128-16AU

    As you probably know, digikey and mouser have no stock. [email protected] www.icplus.net www.sierraic.com & odysseyelectronics.net CLAIM to have them in stock. (but want an arm and a leg for them).
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    Tektronix 2445B Scope Fault

    I don't know of any way to find out actual hours on the scope. Mfgr says it was built for 2,000 hours of no-problem use (just for your info). As always, recommended calibration from the mfgr is once a year. But Calibration is always expensive. And your problem is not a serious one. In your...
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    reset/reboot

    I'm no expert, you'll probably be get better answers from other people on this site. I've been told, rebooting resets your default settings, clears out stuff in RAM (random Access Memory), and basically should clear out whatever is screwing up your system at the time. I'm sure there are other...
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    Cause of blown fuse.

    Ooooo, .... Guilty as charged. I didn't read this as output to the speakers, but then again, ....one more reason to replace the 6A fuses with the correct 3A fuse. If the surge that blew the fuses the first time reoccurs, ... and it's a big one, .... Burry is going to be sitting on two...
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    Tektronix 2445B Scope Fault

    Ok, first I'll tell you probably what you want to know: Your error code is not fatal, and you can keep using the scope just the way it is with no problems. Now I'll tell you what's going on with it, in case you're interested, but I STRONGLY suggest you don't do anything about it yourself...
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    Tektronix 2445B Scope Fault

    The "press A/B trig to Clear" automatically comes up when any one of the power-up test fails, ....that's normal, it's working correctly. When you power-up, scope runs it's own internal test routine, one test failed, giving you the above notification. Routine Test #05 is a test on the main...
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    Good multimeter

    A lot of the newer Fluke hand-helds are pretty good, and they've got some models in your price range. When China first started turning insturments out, they were trash. I don't criticize them anymore, because they're getting better and better every year. Only question I'd have on your Chinese...
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    Remote Controlled flashlight ??

    For on-stage, 'remote' activation, your easiest, cheapest way, would be to run a couple (cheap, small diameter) wires from the two electrical contacts in the flashlight, to the operator at the ends of the wires. He could use a switch or just touch the wires together, to make the switch contact...
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