Horns dead...

[hermitcrab]

I was playing some music yesterday on the Magnavox SS imperial , and noticed the volume was low for where I normally put the control... then I noticed the horns are not producing any sound whatsoever... all music is coming from the woofers ... I am hoping it is something in the crossover because I can't figure out how midrange on both channels quits at the same time...not looking forward to tearing into the sealed cabinets if it is the horns themselves... I have read where these are prone to failure over the years ....

[electra225]

I have a pair of Astro-Sonic horns here that came out of a Stereo Theater. I haven't tested them, but if you need some and mine are good........

Bill is supposed to come out here in the winter. Instead of driving his rig, we could rent him a 24' U-Haul truck. Then we could exchange Arizona and Michigan goodies. I'm sure that would be just fine with him.......

[hermitcrab]

Yea.... that's the ticket...he could be like the U-Ship for the Site members .... we could chip in a dollar or two for gas....

[electra225]

Have you checked to see if the horns are dead? I could check mine to see what they will do. Maybe I should do that first, before I offer you a set of dud horns.

[hermitcrab]

I have not got that far yet, but I have been playing the set , and one side is dead for sure, the other plays at super low volume , I gotta rip the back off this weekend and check it out .

[Motorola minion]

I've got a few extras of the 580069 horn myself but they ARE fixable unless the coil itself is open.

The green plastic cup covers an exposed voice coil, if you pry it off by dissolving the adhesive you can access solder connections to the terminals, good luck.

[hermitcrab]

I am hoping for a bad component in the crossover network, I didn't get a chance this weekend to look at it...

[Firedome]

Ya I was going to suggest xover caps as a primary suspect.

[hermitcrab]

I did change out the woofer caps as I had the correct size , but never touched the tweeter section which was dumb on my part ... after all the caps are 60 years old...

[hermitcrab]

Well tore the back off and pulled the wires off the woofers... nothing... oh boy all the horns are dead... I went to pull the wires for the horns ... POP ... they came back to life... apparently there is just enough dirt/nicotine or grunge on the spades to kill the signal...so on every spade I used a little emery cloth and some contact cleaner and shined them all up... same with the RCA jacks ... I had this happen on a zenith before but it came out of smokers house ... this one does not have a nicotine smell ... must have been just dirt build up?... anyways they are working again , since I went this far I pulled the radio head to check all the caps and will clean it good. hopefully this will solve that problem

[electra225]

Nice job! It's amazing the issues simple dirt can cause.

[William]

Good job, Elton. I'm glad it was simple and easy.

Bill

[hermitcrab]

I got real ambitious, pulled the head out of the magnavox and recapped the whole unit... the preamp and the radio section... then I pulled the R2R and recapped that as well , so now the whole unit has fresh caps everywhere including the crossovers ... the amp I did last year ... only problem I ran across on the R2R was the take up reel would stall ... played with the clutch adjustment to see if that would help but the idler wheel would just stop. I figured the spring that pulls the idler was weak , replaced with a heavier spring , made it worse ... the idler was just barely making contact with the motor and the take up reel at the same time I tore it apart and cleaned and lubed all the linkage for the idler , no difference ... so I got out the micrometer and measured the diameter of the idler, it measured 1. 77.... checked Gary's site for a replacement and that says it needs to be 1.88 diameter ... the idler is worn out... then I remembered I have panosonic that is the same model , pulled the idler out of that and it read 1.86....put it into the maggie and now it plays great... so I have to send in the old idler to get rebuilt... amazing how just .10 of a inch can make a difference..

[William]

Wow, Elton, you have been ambitious. Send some of that my way will you. Do you think the roller wear that much or did someone replace it with the wrong one? I'm glad you had a spare and got it sorted out. I remember seeing that Maggie and it's a monster.

Bill

[hermitcrab]

I had the set apart for the horns , I figured just do it and get it over with... only took me a couple hours each for two days , having a solder sucking gun makes all the difference ... the R2R I knew the idler was worn , I put some rubber re-new on it a few years ago , so I can't complain too much... but it got to the point of playing a tape and worrying whether the take up reel was working or stalled spilling tape all over the place... I also recapped the remote control box for remote operation as they were high ESR and one was open... but sadly it did not fix the problem ... so it needs to be tuned to the right frequency ... I kinda get nervous when playing with those tuned cores... I have broken a few just from the age of the graphite ... so I should leave well enough alone ...