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Topics - Motorola Minion

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1
Music / Aretha Franklin
« on: August 17, 2018, 08:08:54 AM »
As we have lost one more great talent, I was fortunate enough to hear the Queen of Soul cover "Long and winding road" in a way Paul and the Beatles probably never imagined. I had just missed her cover of "walk on By" unfortunately. So I'm looking on youtube now and imagining how it would have sounded.

Her vocal range was all the more sweet and nostalgic heard through a 1965 "last of all tubes" Zenith Console as I boxed in the speakers. Being one of the last all-Beatles songs, it was always bittersweet anyway, yesterday it was more so :'(

2
I want to preface this by saying that often, changers seem to work fine mechanically. When they don't, you need to mean business, so get down and dirty!

For oiling spinning metal parts, Zoom-Spout turbine oil must bein every record player toolkit. 3 in 1 type and sewing machine seems like appropriate vintage oil to use BUT it is generally sloppy and attracts dirt. Less is better, always.

I used to HATE doing record changers during the 80s, preferring the carried-in 9" to 20" TVs. The TV road tech pulled the changers from consoles and brought back to the shop for us bench toads, and as you can guess, peak season was October-December.

Doing changers was fun - like taking out the trash, so our service manager had a no-fail 8-step method we used on BSR, Magnavox and RCA units pulled from consoles and brought back to the shop by the road tech. "Just do it" I was often told when I verified it was operating correctly, and already looking for a new stylus (often in vain) in the dusty parts drawers.

Lubriplate or white lithium grease ( aka GC's Phono lube) is mandatory for all sliding parts. Go in ONCE with your best stuff and you'll own the repair. Just do it all, forgetting anything will make you repeat those annoying processes.

Isopropyl alcohol (IPA) and alternately, lacquer thinner, Q-tips and shop towels are all that is needed to clean off dirt-encrusted grease. it also does a great job on motor capstan "stepped shafts" plus the inside of the platter along idler track

Rubber-Renu is highly reactive oil of wintergreen and seems to work on most but NOT ALL idler pulleys to remove glaze. Only slightly more effective than IPA. If the pulley has deep fissures in the rubber, it probably overheated when the player motor was left on when it stalled, basically finishing off any chances for a lasting revival. Bite the bullet and replace it.

Bottoms-up work first

1- Mandatory motor maintenance - mark positions of every nut, 6-32 screw, washer, spacer and bearing bracket before you take ANYTHING apart. Soak those bearings first with IPA, using a cotton swab to pull the gunk out. Soak next with Zoom Spout or similar super-thin stuff.

2- Clean the changing mechanism with IPA and shop towels, and yes, you must take cycle gear-wheels off shafts or sliders out completely. Sliders on V-M players are tricky but you will not be successful without a thorough disassembly - cleaning and lube. trip levers that slide must be cleaned and having another player along side to compare whats out of place or bent cannot be understated.

Topside last

1- Pull off the platter from spindle. RCA's need a snap-ring pliers, Mags and BSR use a C-clip and V-M's use a small plastic O-ring and grooved center pin. Most are easy but on BSR's - spindle grease turns into JB weld, and must be soaked with lacquer thinner or worse to get it loose, spin-able and removable. I have yet to try "weasel piss" (WD40 or PB blaster) as it is hard to limit overspray.

2- Take idler pulley off and give it the business with IPA and oil the shaft/spring washers. Check alignment with the motor shaft thru all speed settings. If it does not land in the middle of a step, motor mount grommets are flat/gone OR if solid, it may be improper idle shaft washer placement.

3- Move center pin in/out, up and down while dousing with IPA to get ALL the crud out that causes it to drop two records or operate sluggishly. The tiniest bit of oil is all this part needs.

4- Platter spindle cage/ball bearings and washers need a thorough soaking and de-gumming, here we had success with lacquer thinner also. Pay attention to sandwiching the bearing between TWO thin washers. They like to stick and drop off during disassembly. To keep from hunting parts like those washers and center pin balls (V-M) that bounce off the bench, do your disassembling in a dishwashing tub or big cafeteria tray to catch anything that cuts loose.

5- The grand finale included checking speed with strobe disc under light from incandescent or fluorescent on magnetic ballasts. Try all record sizes/rpms and verify it worked on the 45 adapter, run through all cycles and at 78 (or 45) rpm to distribute all the oil and exercise every operation.

It always worked, no call backs, all the more reason to love Magnavox and RCA changers in particular.
About 5 years ago, I had to re-learn the whole process for Voice-of-Music changers, used in all my Motorola and Zenith tube sets.

I may post a thread on V-M by itself, renowned as rugged YET labor intensive to disassemble and re-assemble :P.

3
Astrosonic and Other SS Magnavox's / 1966 Imperial 2RP701 repairs
« on: June 28, 2018, 11:53:16 AM »
This tale is a short one but I thought it necessary to help anyone who is working on the better quality Astro-sonic chassis. This one has the R207 tuner-preamp and A575 100-watt amplifier. The record changer is a W603 Micromatic, a bit hard to remove from a cabinet with everything compartmentalized.

This console has a few doppelgangers, including the popular "Francisco" 1RP679, which has one set of horns, not a pair for each channel.

The repairs were very straightforward. About thirty 5 thru 500 uf black Nichicon capacitors were needed, with many of them testing open. As with most of this era Magnavox, the power supply positive is grounded to chassis. the amplifier has both positive and negative supply voltages.




4
Other Tube Console Brands / General Electric Tube console
« on: May 30, 2018, 01:57:32 PM »
I just picked this up on a trip upstate, from the original owner. It was probably bought at a small-town appliance store. As you can see from the photos, its pre-1964 due to conelrad marks on the AM scale. It claims FM stereo although it does it on the cheap, with one tube. I have seen this GE tuner in a few other models, like TV-stereo combos.

I was expecting a GE changer but this is a Voice of Music and appears original. The 8"/ 3" speakers are probably the most a single-ended 6AQ5 output tubes can drive.

Overall, this is a lightweight console but interesting nonetheless. GE had to make mid-priced and expensive consoles, but I have not seen one to date.

5
Motorola / Pre-stereophonic High Fidelity Motorola
« on: May 30, 2018, 01:42:55 PM »
I'm having a look at this. The seller is "moving and wants it gone". I have not seen a Mono HiFi from Motorola before.

6
Sightings / General Electric Tube console - PA
« on: April 27, 2018, 01:34:32 PM »
I'm going upstate next week and plan to stop and check this out. As it has been said elsewhere on this forum, you can never have too many tube consoles.

Right now, I have a tube stereo console from every major manufacturer except GE. This is the best example of a tubed GE I have seen to date. I'm sure there was a more deluxe model, but the lack of brochures and advertising makes that uncertain. Musaphonic was a name for such a model in the late 30s and 40s.

Since I am very familiar with GE televisions of this era, I am excited at the prospect of owning the HiFi equipment.

7
Motorola / Motorola Stereophonic SK107 - Phono with Vibrasonic
« on: April 20, 2018, 02:32:41 PM »
I picked up another Motorola on a trip upstate after seeing on CL and being the only one willing to pony up $25. Its the SK107 ($300 new), which has no radio but does have the "Hammond-licensed" vibrasonic unit built by Gibbs Manufacturing of Janesville Wisc. It is one of the more economical three-channel models having a 10" woofer, two 6" mids and two 3" cone tweeters. I am expecting to sell this one, as my other two are more expensive models, not to mention a tad LOUDER :P

I opened it up to see a the same pre-amp used in more expensive models, but an interesting amplifier that uses two SE 6BQ5 (Mullard OEMS) and the usual pair of 6V6GTA for the push-pull bass channel.

It looks similar to my SK112 ($605 new) but the amp is 20 watts versus the usual 51 watts. Both have the same early-American cherry veneer, not the sought-after Drexel cabinet models that many seem to have and are usually priced accordingly.

8
Tube Consoles / Missed it by "that much" - a recapping tale
« on: April 20, 2018, 01:56:50 PM »
After performing a full recapping on a mid-level 1964 Zenith stereo amplifier that uses SE6BQ5 and 1-12AX7 , I was greeted with a loud, irritating oscillation upon power-up.

Rather than hearing silence with the volume set at minimum, a loud 700 hertz (or thereabouts) blast filled the shop and beyond one early morning in February.
Turning up volume, audio from the restored tuner came through but still, I had just enough time to kill power to stop it.

Not fast enough, this prompted the upstairs tenant to complain to my normally patient landlord/owner (who is Amish) via a "building manager" (a demanding RE agent that he hired to manage tenants), prompting me to be banned from my shop before noon. Sheisse!!! I am preparing a new space in a barn on the same property. More on that in another post, probably in chat.

Coming back later that day when the coast was clear, the volume could not be reduced, the tone controls had little effect and neither did the bass-boost switch.

No usable clues except pulling the 12AX7 made it quiet. Not knowing where to start, both the Zenith factory and SAMs Schematics were double-checked to see if my nearly 100% re-cap missed any values.

Even the normally OK Zenith-made ceramic disc caps of .01 and .0033mf, 470 and 220 pf had cracks in them, prompting a replacement along with bumblebee, dipped paper caps and electrolytics including some resistors. I want this console to sound as good as possible, being the last of the all-tube Zeniths.

 Today, I thought to bring in the chassis and schemos and scrutinize it over my lunch break under very bright lights. The cause found was a capacitor in each channel being off by one order of magnitude, I used a .0033 instead of a .033 mf. This was in the feedback loop that runs through the bass-boost switch.

Lesson learned: Even though I wrap leads of replacement caps around the existing cap leads before soldering and clipping old caps out, I missed it somehow ???

9
Sightings / Magnavox color theatre Singapore 21 - PA
« on: April 17, 2018, 12:36:51 PM »
This is an entry-level 15 watt solid state stereo receiver and all-tube TV chassis "series 45" or U450 - but record changer looks newer

Was $795 new according to magazine ad showing it as model "546". 1965 catalog lists as model 2-T564 for $750, so it may be a 1964 held-over (prefix 2?) until producing more rectangular screen color.

CRT cataract is an easy fix, and if I had room, would be worth a 3 hour drive at that price too.

link to ad https://pennstate.craigslist.org/atq/d/antique-tv-record-player-radio/6561195424.html

The prize theatre IMHO would be a 1962 model using the "series 37" (RCA CTC11 clone) TV chassis and an all-tube stereo
.

10
Other Tube Console Brands / Sylvania SC541w final all-tube model?
« on: March 26, 2018, 12:45:14 PM »
I found this on local craigslist. The seller got it from an estate sale and planned to make a liquor cabinet from it, but decided it needed too much work.
It sure needs some cabinet work. There were lots of 45s and LPs inside it but no paperwork :(. The Garrard changer probably was used hard.

The amp uses 3 7025 (12AX7) and single-ended 7868 outputs. Tuner has built-in mpx decoder, similar to a Zenith using a 6EA8

There was a model a step above this one with push-pull 7868 output tubes, same as what the Fisher 400 receiver used. I have the sams 719 with that one in it.

11
Sightings / RCA 1962 console - electronics worth more than cabinet
« on: March 08, 2018, 10:46:48 AM »
https://frederick.craigslist.org/atq/d/rca-console-with-stereo-and/6519394589.html

I like the electronics in these so much, similar to my nicer-looking VCR244, so Ill put up with the cabinet

12
Sightings / Silvertone N of Baltimore
« on: February 27, 2018, 03:33:43 PM »
https://baltimore.craigslist.org/ele/d/vintage-silvertone-hifi-radio/6510918060.html

Not your average Silvertone, by the looks of that power transformer

13
Sightings / Webcor Musicale Coronet - PA
« on: December 01, 2017, 01:17:00 PM »

14
Electronics / OEM caps measure high - PB solid state pre-amp
« on: November 21, 2017, 11:31:43 AM »
While working on the preamp section of a 1966 Packard Bell Console RPC-66, covered by SAMS 902, I have found some common Nichicon caps, the last few I need to replace.

The problem: C315 and C316 are labeled as 25 mf @ 3 volt and measured 124ufd (!) on a Fluke DMM.

C317, 318 and 319 labeled 50 uf @ 6V measured 221 ufd. I will double check on the EICO 950 but expect the same and checking for breakdown voltage, which the 950 does up to 500v, on a 6 volt cap is just impractical.

Note that my intended new replacement caps, measure 26 and 48 uf respectively. I'm used to original parts measuring lower, but not this.

Do these caps fail by increasing in capacitance? I expected a decrease in capacitance attendant with an increase of ESR.

15
Consolettes / General Electric and porta-fi
« on: October 05, 2017, 08:57:07 PM »
Its not good to have a year since the last post in a forum but this is one is asking if any one has a GE in that wall-mounted cabinet with either a Garrard or GE changer.

I recall their early solid state amps mated to tube tuners on some. 16 ohm speakers ?

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