Recap Motorola HS-677

[berkemo]

Hi All. New to this site/forum and first off thanks to everyone for posting great info throughout this site! This is a tremendous resource and thanks for your time.

I just got an old Motorola Console (it ran quite well on a very brief test run) and I'm going to be that rookie guy who tries to recap it. I've checked out all sorts of info, downloaded the schematic and I'm beginning to better understand the rudimentary concepts.

I'm ready to jump in but would really like to get some more experienced eyes on it before I dig in. I'm planning to replace the electrolytic caps for sure and probably most of the cream colored (paper?) canister caps. A couple of questions:

• This looks like I can use the chassis as a ground. I see a couple of spots near the electrolytic can for the e-cap grounds. Can someone confirm this?
• I'm expecting to replace the cream colored (paper?) caps. Recommendations?
• Notice any other obvious visual issues with this?
• Should I replace the sand resistors?

My goal is to get these basic updates before running it for any length of time. I don't have any testing equipment other than a basic multimeter so I'm not planning to evaluate/tune this thing right now.

Thanks in advance for any input!

 

[raycarr00]

 

[berkemo]

@raycarr00 Got it. Fixed. My first post on this site and I blew the image upload. Appreciate your help.

 

[raycarr00]

yes, replace caps, resistors...except the ceramic discs that are tied to ground, unless they're burning-up. up the voltage rating on the caps. reflow ground and other connections with fresh solder. avoid carbon comp resistors, as they drift a lot.

 

[cademan]

Pics of the top of chassis. You do know that this is a mono unit.

Unless the sand resistor reads open or out of spec, I would leave it alone. If the receiver is working, that resistor is not open.

 

[berkemo]

@cademan I added pics of top chassis. I've got some cleaning to do! The receiver is working - does that suggest I should change out the resistor? Yes I know it's mono. Wanted to explore that era with a typical piece of audio gear. Found this console for for $30 so I figured I'd try it. It has a stereo out to an optional powered extension unit but I'm not interested in that right now.

 

[raycarr00]

I'd leave the large high pwr resistors if they're within spec, change burnt wiring, diodes, wire high voltage caps under multi can cap n disconnect it completely...jazz sounds good in mono.

 

[cademan]

It has a stereo out to an optional powered extension unit but I'm not interested in that right now.

This means that the turntable has a stereo cartridge. If you want to listen to mono recordings solely, you will have to change out the cartridge for a mono one.

 

[berkemo]

Thanks all for the input! Greatly appreciated. I have a question on the electrolytic can replacement. Planning to add the replacements under the chassis, does it look like I’ll need a terminal to connect everything for it. Thanks.

 

[raycarr00]

just connect them as you please per polarity and isolating the positive. just disconnect the can completely. you can use its ground.

 

[berkemo]

Thanks to all for your input. Finished recapping and very happy with the results. This amp sounds great. Now on to some radio issues!

 

[raycarr00]

fyi: those carbon comp resistors are notorious for being out of spec and drifting. metal films are a good alternative.