How to signal trace weak channel Vintage Midland 19-548 stereo receiver audio generator oscilloscope

Midland transistor type home stereo receiver from the early 1970's. This unit was brought to the shop by a local fellow. This receiver was his pride & joy. Many fond memories. He told me as a kid, he earned the money to buy it through shoveling walks and mowing lawns. Over the years one channel became weak. Although this radio has little value, it meant more than money to the owner. I considered it a fun challenge, as I have not worked on something like this in over 30 years. Scouring the internet, I found no information on the model 19-548 Midland. So, I had to do my best to trace the PCB signal path. Got lucky to find an open coupling cap. There was no charge for this repair. I am following up with the owner for a complete cap job to ensure some longevity.

[@bigmsound]

This definitely looks like it was made by Roland Electronics in Japan. I came across a Roland stereo receiver marketed under Roland's Martel / Telmar branding, on Ebay a few years ago and It has the same chassis inside. It was a Model 100T or variation, and from 1968. Those "LiLLy" brand Japanese electrolytics and vintage "Midland logo" give away It's age. A very nice budget receiver for It's time and a great repair. It is most likely better quality than any of the current budget receivers of today. It is definitely worth recapping.

[@goodtimejohnny8972]

If only there were great techs like you in every town across America. Love the work you do. Thanks for passing on the knowledge.

[@DeadKoby]

Funny enough... with any older electronics, if you guess capacitors, you're correct more often than not.

[@zbaby82]

I love it when electronics get repaired.

[@johnrazor8720]

Very clear troubleshooting. Thanks for the lesson.

[@edwardhannigan6324]

Nice fix, love the info and remedy..More knowledge for my old brain..Ed..UK.😊

[@hestheMaster]

Always impressed by your troubleshooting Terry. Best I could find is this Midland receiver was made in 1970.

[@brentnearhood8874]

Thanks! Terry 🚗 Glad there wasn't a car crash into the amp!

[@VideoRanger]

Nice video. Thanks OM.

[@g.fortin3228]

Very good.. !! great to learn how to back trace logically. thank you!

[@bobblum5973]

Nice video, Terry! I always liked the styling on that era of Midland gear (and others, too!). A good balance of metal, black, the rocker switches. Plus the bands are labeled in megacycles and kilocycles! You demonstrated one of the nicest things about working on stereo gear. When one channel is working and the other isn't, you have an example allowing you to compare the two and spot the differences.

[@Team-fabulous]

Really interesting,,, D-Lab rules

[@worldwide1376]

Thanks, Terry, for another great video. Cheers! -Norm

[@Homer19521]

Nice. Looking forward to an RF signal trace exercise.

[@mumbles552]

Well done. You make it look so easy!

[@nazeerabdulrahuman9526]

Nice video ❤❤❤

[@f.k.burnham8491]

In my experience of 55+ years of electronics repair, one should not jump a capacitor with the power on. It can "heal" the bad capacitor. I learned that lesson the hard way many decades ago. The best way is to tack another cap in place with solder or jumper clips with the power off, then turn the amp on. Yes, on something that old it is best to recap the entire amp. I suspect the ESR on the caps is through the roof on most of them, and another failure is in the near future from the old caps failing.

[@Brian-yt8fu]

Could be the customer only wants to replace the parts needed to get it working again.

[@russellhltn1396]

@@Brian-yt8fu Pay me now or pay me later.

[@Brian-yt8fu]

@@russellhltn1396 you're right those caps should all be replaced.

[@ivetoldyouonce]

Nice job!

[@midmodaudio6576]

Love your videos. It would be helpful for those of us less experienced if you could refer to a schematic.

[@d-labelectronics]

I could not locate a schematic on this model Midland

[@midmodaudio6576]

@@d-labelectronics I see, thanks for the reply. I always learn something from your videos.

[@suhailasaba1051]

Great video. Question: Do you have a video showing how to align radio frequency or intermediate frequency stage in a transistor radio receiver ?

[@kylenovak97]

Thanks!

[@mumbles552]

Rookie question. It was hard to see but did you have the ground lead on your probe clipped onto chassis ground somewhere? Thanks.

[@MrDeticus]

Hello Mr D=Lab. Thanks for the interesting video. I have a question for you, if you don't mind. How would you troubleshoot a weak signal in the clean channel of a high gain tube amp? I am working on a Krank Krankenstein amp. It is losing a lot of signal in the tone stack. I understand some loss is expected, but I don't know how much. I can't determine if I have a problem or if it is just normal loss when EQs are turned down. Thanks for any help you can lend.

[@tubeDude48]

I sent you an email with lots of links to manuals at my web site 👍

[@danielcrook9504]

Hi Terry...I have a 1971Fenfer Pro Reverb that has developed a ticking sound when playing through the Vibrato channel but only when a tube is in position V1.Can you tell me how to repair this annoying sound, not very loud but noticeable. The amp has a brass plate soldered along the knob panel and it has been blackfaced. Where do I start ?

[@d-labelectronics]

Send me a direct e-mail & I will send you a diagram to resolve that tick

[@merpolis93]

Can you use any audio input instead of the dummy load when probing? i.e. the radio?

[@kenwhelan3003]

Leader Lag 25...where can I find one? Plenty of 125s.... significant difference?

[@d-labelectronics]

I found this one on ebay. Never had a 125, so do not know how well they perform

[@kenwhelan3003]

@@d-labelectronics thanks for the response I'll keep on looking...

[@jdmccorful]

Well done, good demo. Thanks.

[@dr.detroit1514]

A great tutorial on signal tracing, thanks!