ROWE MM4 Search Unit

[f16bmathis]

Hey, Rowe MM4 had been sitting for years. The Search Unit motor barely turned when I started it up, but manually rotating it, it would select the record I wanted. I lubed it up, electrical cleaned the board..... Now the motor runs, but after the first relay (K1 or S1 depending on where you're reading it) finds its way, the second relay (S2) never does and the motor keeps running until I manually push the relay and then it plays whatever record I randomly selected.

I checked the relay R2 and it does latch and stay latched. Also checked S1 & S2 relay ohms and got 75 +/- on S1, and a very low reading on S2, but applying power to S2, the relay easily clicks over.

I also pulled the board and cleaned it thoroughly, then did the adjustments checks to both wiper arms.

My thoughts are that the relay (reed switches) may need adjustment to the .010 settings, they are slightly larger, or what I don't know. Hate that it was working till I got the motor working. May be it never really worked unless it was going slow, which would then be a timing issue?

Thanks for any help!

[Ron Rich]

Hey, Backatcha,
"Reed switches"--- What are you calling "Reed Switches" ? What is "slightly larger" ? What did you "clean that board" with ? Ron Rich

[f16bmathis]

They call the reed switches S1 and S2. I cleaned it up with electrical cleaner spray can. And wiped it with a cloth. Slightly larger means it looks bigger than .01, I didn't have a feeler gauge so maybe 1/16" to 1/8" maybe. 

[Ron Rich]

I am at a loss--"reed switches" are magnetic activated type switches-- I do not recall any "reed switches" in that unit ?
Please read our FAQ's section on contact cleaning-- IMHO, "spray can contact cleaner" is usually not appropriate, for make & break type contacts.
Ron Rich

[f16bmathis]

Sorry you don't understand. My verbiage is not the best, and I take it you need an exact description of the part I am talking about. As I said in the 1st post, the "reed" switches are called out as S1 and S2. They are called relays. To me they look like reed switches, attached to relays. Some magnetism involved. 

If you don't know what I'm talking about on this particular machine and this particular search motor, then you are probably not the person I need to be talking to.

I don't intend to sound mean, just working every day after work to get this running and I need someone who knows what I'm talking about, or I'll just eventually figure it out. I always do... eventually!

Thanks for trying!

[f16bmathis]

Aha! Fixed!! Now on to the next problem, it seems to miss pick certain records. F2 was picked as F2, but A1 picked something else as did a few others. I'm going to chart it out and see where the pattern is.

[Ron Rich]

PLEASE -- As requested in the "Hi Newbies" post in the FAQ's section--Tell us what you found ! Ron Rich

[f16bmathis]

The fix: So I'm not near the machine and fixed it a few weeks ago, but as I remember... My verbiage will not be "accurate" either so bear with me...

So I took apart the selection button assembly, and saw the main coil that activates when the machine is turned on. This coil allows selections to be made. When a selection is made and the search unit finds it, the coil then dis-engages to release the buttons. It will also not engage if the machine is not in the "run" position, or there are no credits. There are two smaller "reed" looking coil relays to the left (from front of machine). One is active. When a selection is made, the search unit goes around and when the search unit contacts are made, the coil (I believe to the right) that is active, de-energizes and the coil relay to the right activates and deactivates quickly when the unit is working. I checked the relay "reeds" and found one to be rather high ohms. A little contact cleaner and a little sanding, and now it finds everything.

I hope this explains it well enough to help a novice. I do plan on taking some videos and posting them on you-tube to show the operation, removal of components and component locations. Eventually also covering amplifier capacitor repair, and selector thingy adjustments. I may even be able to link those here, but I'm a novice. Background mostly in Air Force F-111, (Yup I'm old) , F-16 Avionics, home made electric Vehicle, converted a Chevy S10 into a 115 mph EV, and currently a Fanuc robotic and Automation Engineer. So good with tracing sparks!

[wdln]

Sounds like you've got a good handle on what's going on with it. I'm currently working on an MM-6. If you haven't already, it's also a good idea to thoroughly clean the contacts on all the interconnecting cables, as well as warm up cold/cracked solder joints as Ron details here:

jukeboxaddicts.proboards.com/thread/483/common-rowe-connector-more-problems

You'd be surprised what kind of intermittent issues bad contacts can cause, even if they visually look OK.