Author Topic: testing while on the bench  (Read 1120 times)

Tedrick

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testing while on the bench
« on: January 29, 2018, 06:06:16 PM »
Hi Group -
here's an issue I've been bumping up against - while working on the receiver in my current project with the receiver out of the cabinet, it's kind of a pain to hook up the various umbilical cords and molex connectors into the receiver in order to run the unit for testing.

does this just go with the territory, or are there ways around plugging and unplugging stuff between tests?

should I be able to hook up test speakers to the pins on the connector going out to the console's speaker network?

how about power? Could I run a temporary connector into the molex to jump start the system and not power the record changer?

Thanks!
Ted

Tedrick

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Re: testing while on the bench
« Reply #1 on: January 29, 2018, 08:19:50 PM »
just had an interesting problem probably due to careless disconnecting/reconnecting -
I lost one channel and while investigating I pressed and wiggled the output board slightly and the missing channel popped back in --

hmm.... hopefully that problem doesn't come back....

TC Chris

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Re: testing while on the bench
« Reply #2 on: January 29, 2018, 08:59:43 PM »
Bad contact? Board trace broken?  Dirty connector? Probably better to try to identify the issue before you put it all back together, because if you don't the problem will show up again the very moment you tighten that last screw.  The voice of experience....

Chris Campbell


Tedrick

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Re: testing while on the bench
« Reply #3 on: January 29, 2018, 09:52:59 PM »
good point --
I'm hoping it might have been related to over use of deoxit...
I'll wipe the contacts down with isopropyl alcohol --

Tedrick

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Re: testing while on the bench
« Reply #4 on: January 30, 2018, 10:08:32 PM »
ok - figured out how to connect up test speakers without using the molex connector to connect into the console speakers -

helpful to be able to test without that molex connector in there --

I see I could wire up a temp plug for main power --

I could leave the big connector for aux and phono and still use the unit -- so I'm making progress --

Tedrick

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Re: testing while on the bench
« Reply #5 on: February 01, 2018, 10:02:31 PM »
got the receiver chassis set up away from the mothership -- feels good --

temporary power -
temp aux -
speakers -

all over but the cryin'!

for aux, I wired up a stereo 3.5 mm plug, ground to one alligator clip, left center strand to another and right center strand to another - so I'm able to feed in signal for testing and tracing -

speakers - similar connectors off the  left | ground | right  pins --

next step would probably be an adjustable vice/cradle for holding/rotating test piece -- any tips for this?

T

ed from Baltimore

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Re: testing while on the bench
« Reply #6 on: July 26, 2018, 07:24:43 AM »
              Well, its been a few months so you aren't in the middle of a project anymore, but since your hookup problem is so universal I may as well tell you what the bench at the bench servicemen did at the tv repair shop  I worked for forty years ago ordering parts. They were the guys who never went on service calls because they knew how to troubleshoot down to the component so the others would call at the homes and try and fix the large heavy  console in the field with all those modular boards they carried for  each brand.   If it wasn't repairable in the field they would unplug t4ons of wire harnesses and bring in the naked chassis for the bench tech.
      The bench tech would connect up the yoke, t4he picture tube neck socket, the HV lead and maybe the convergence board to the equivalent parts for the brand being fixed and sli[ the yoke and converence circuit loosely over the picture tube neck. Then he could power up the set (the tuner usually came n with the chassis) and troubleshoot the chassis. After replacing the bad componen on the chassis the serviceman brought it back to the home, reconnected all the connectors and hopefully the set was fixed.
       The point is this.....they had made up plug in harnesses that would mate up with all the molex connectors and they didn't need alligator clips or any temporary jumpers. to wiggle loose and interfere with efficient troubleshooting. The next time you get a junker or part out a similar unit for your prized baby, you may as well keep all the nice long Magnavox harnesses and plugs to do a quick hookup to your good chassis because you will always be taking it apart again, rest assured you will, you can use the alligator jumpers to go from stripped wires to the speaker and AC plug and even an external balance pot. It saved the TV chassis service guys a lot4 of time.