Teardown and fix this RCA Transistor Tester from 1967!

This RCA WT-501A Transistor Tester dating back to 1967 was a very neat find at an antiques place recently, so I had to pick it up. Turned out a bit crustier inside than I was expecting! Let's get it working.
If you like what I do and want to encourage more, I appreciate your support through likes and comments below. If you have the means, you could also support me on Patreon as money helps me buy broken things to fix and build more projects - / silvervest
Any feedback is welcome, as always.
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Music:
* ELFL - Low Fidelity Space Waves
* Masaru Setsumaru - Data Select (from Sonic 3)
Font: Riciery Leal - VCR OSD Mono (www.dafont.com...)
Putting up with my weird hobbies: My wife
Disclaimer!
I am NOT an expert, I have genuinely NO idea what I'm doing, and mostly just glue things together and use a lot of Google-fu until stuff works. I've been tinkering with electronics since I was a kid but have no formal training and will probably do things incorrectly. If you learn something from this, that's awesome, but trust me - I'm learning too!
#rca #electronics #repair

[@Robbie1949]

I bought one of these and was thinking of doing the same thing with the batteries. Putting in battery holders but if you read the service manual which is downloadable from Electrotanya ( it's the best copy). RCA say the reason they are soldered in is to eliminate any slight resistance that would exist in a battery holder. The Chinese D size cell holders do have this problem. As quite a bit of current is drawn in power transistors under test it makes sense to keep cell resistance down to a minimum. Use leak proof 1.5V D cells in this application. The worse I have found are Duracell but cells usually leak when flat so a check every few six months should be done. Read the Service manual. I am an degree electronics tech and have served in the RAAF for over 20 years and in the trade for over 50 years now. Regards Robert

[@silvestronsbitsandbytes]

I did find the service manual, but clearly didn't read it close enough to find that! What an amazing insight, thanks Robert. I would never have thought about the impact the battery terminals would add, but like you said when testing power transistors everything matters. I settled on some AA holders and am using Eneloop rechargables, which seems to work okay. I wonder if the voltage difference between a regular 1.5v alkaline/lithium vs the 1.2v NiMH would impact as well?

[@Robbie1949]

Yes it will , use D alkaline cells. Rechargeable cells have no place here the tester was designed to use 1.5V cells. There is not much point in using an instrument that is not anywhere near accurate. I think you would be well advised to learn some theory. It appears you have a lot to learn on electrical and electronic theory . These transistor testers are not complex but require knowledge and understanding you seem to lack , as you mentioned yourself. I taught electronic theory to trainees in the RAAF in my final service years as a SGT instructor. If you are taking up a hobby it pays to learn basic electrical principals then progress into electronics from there. There is much to learn and fully understand. Regards Robert

[@orpiv]

The original batteries had RCA labels

[@mikedfgfj]

Considering the "repair" was just a change of batteries, this was a lucky punch.

[@silvestronsbitsandbytes]

Oh absolutely, much more of a clean up than anything. As the old saying goes, they just don't make em like they used to!

[@JendaLinda]

If you're not going to use this tester regularly, perhaps t's best to not keep baterries inside and just note the voltage and polarity.

[@silvestronsbitsandbytes]

Yep I didn't record it, but I've now put some AA battery holders in where the D cell holders go, so I can drop in some whenever I want to use it.

[@Robbie1949]

As mentioned before D cells are required for the longevity and current drain on the cells. AA cells just are not good enough in this application. RCA didn't put them there for fun or because they made money out of D cell manufacture and sales. Regards Robert