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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Help please with Tek 465 problem
I recently bought a Tek 465. It was working fine, but now scope
traces aren't sweeping across. Just a pair of dots where channels are supposed to be. I'm not too familiar with this type scope and was wondering if it's possible that I accidently moved a control and lost the sweep. I've pretty much tried everything in the way of fiddling with controls. But maybe secret button somewhere I don't know of. Ok, so assuming it's a problem inside scope, what am I looking at in the way of circuits? Obviously there's a sweep oscillator generating I would guess a sawtooth. Is there some kind of integrated circuit with a Tek part number on it that's not going to be easy to get hold of? Or am I likely to find run of the mill parts that I probably have kicking around. I guess what I'm asking for is for someone to take a peek at schematic and give me thumbs up or down. I have another scope and my troubleshooting skills are good, just don't have schematic in front of me. If job is no-brainer I'll get hold of a schematic and go for it. Otherwise have to ship it back to guy I bought from and pay him to fix and ship back $$$. Thanks guys. Regards, Bob |
#2
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Help please with Tek 465 problem
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#3
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Help please with Tek 465 problem
Does vertical deflection work? I lost horizontal on mine once when a wire
fell off the deflection pin on the CRT. "Yzordderex" wrote in message om... I recently bought a Tek 465. It was working fine, but now scope traces aren't sweeping across. Just a pair of dots where channels are supposed to be. I'm not too familiar with this type scope and was wondering if it's possible that I accidently moved a control and lost the sweep. I've pretty much tried everything in the way of fiddling with controls. But maybe secret button somewhere I don't know of. Ok, so assuming it's a problem inside scope, what am I looking at in the way of circuits? Obviously there's a sweep oscillator generating I would guess a sawtooth. Is there some kind of integrated circuit with a Tek part number on it that's not going to be easy to get hold of? Or am I likely to find run of the mill parts that I probably have kicking around. I guess what I'm asking for is for someone to take a peek at schematic and give me thumbs up or down. I have another scope and my troubleshooting skills are good, just don't have schematic in front of me. If job is no-brainer I'll get hold of a schematic and go for it. Otherwise have to ship it back to guy I bought from and pay him to fix and ship back $$$. Thanks guys. Regards, Bob |
#4
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Help please with Tek 465 problem
Put both A and B trigger in normal position. Put mode in auto, put scope in
A sweep only. Trigger levels to "+" and midpoint Three basic sections - horizontal amp, trigger generator, sweep generator. If the hor. position knob moves the dots, it's a good bet that the horizontal amp is good (or try the XY mode ). If you have Trigger pulses from the gate outputs on the back of the scope, your triggers are working. To check the sweep generator , you need to get inside and have a schematic. Theres a load of other signals such as blanking, holdoff etc - the manual is a must for these things. Yzordderex wrote in message ... I recently bought a Tek 465. It was working fine, but now scope traces aren't sweeping across. Just a pair of dots where channels are supposed to be. I'm not too familiar with this type scope and was wondering if it's possible that I accidently moved a control and lost the sweep. I've pretty much tried everything in the way of fiddling with controls. But maybe secret button somewhere I don't know of. Ok, so assuming it's a problem inside scope, what am I looking at in the way of circuits? Obviously there's a sweep oscillator generating I would guess a sawtooth. Is there some kind of integrated circuit with a Tek part number on it that's not going to be easy to get hold of? Or am I likely to find run of the mill parts that I probably have kicking around. I guess what I'm asking for is for someone to take a peek at schematic and give me thumbs up or down. I have another scope and my troubleshooting skills are good, just don't have schematic in front of me. If job is no-brainer I'll get hold of a schematic and go for it. Otherwise have to ship it back to guy I bought from and pay him to fix and ship back $$$. Thanks guys. Regards, Bob |
#5
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Help please with Tek 465 problem
"bg" wrote in
: Put both A and B trigger in normal position. Put mode in auto, put scope in A sweep only. Trigger levels to "+" and midpoint Three basic sections - horizontal amp, trigger generator, sweep generator. If the hor. position knob moves the dots, it's a good bet that the horizontal amp is good (or try the XY mode ). If you have Trigger pulses from the gate outputs on the back of the scope, your triggers are working. Point; I believe the gates are present when the -sweep gens- are producing a ramp,not when a trigger is present.But in AUTO mode,you don't need any trigger to get a sweep,it's free-running. To check the sweep generator , you need to get inside and have a schematic. Theres a load of other signals such as blanking, holdoff etc - the manual is a must for these things. -- Jim Yanik,NRA member jyanik-at-kua.net |
#6
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Help please with Tek 465 problem
Thanks guys.
Couldn't get scope going, but guy I bought it from is going to swap out for another reworked unit no charge. He's good to deal with and going out of his way to make me a happy customer. Happy Holidays Yzordderrex |
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