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Topics - Motorola Minion

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1
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.

2
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.

3
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 ???

4
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
.

5
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.

6
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

7
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

8
Sightings / Webcor Musicale Coronet - PA
« on: December 01, 2017, 01:17:00 PM »

9
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.

10
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 ?

11
Other Solid State Console Brands / Packard Bell RPC-66
« on: October 02, 2017, 11:30:03 AM »
I'm working on this solid state console that probably needs caps among other items. The voice of music changer is branded PB also but uses an odd cart.

Has anyone here worked on a PB before. I have a Sams 905 for the RPC-56, hoping its close. Pictures once I open it up.

12
RCA / RCA Victor VCR-244
« on: September 21, 2017, 03:18:13 PM »
I got this about 2 years ago along with a Sylvania SS console for $40 with some other stuff. I was not in a hurry to find out how bad it was inside after I read Larry's thread on one in similar condition. I was pretty sure I would get around to it soon and then a second and much better condition RCA 3VF516 showed up.

So I decided to take it and sell it along with my usual selection of old radio/tv stuff so I took it to the twice a year, mostly antique radio swap meet at Renninger's in Kutztown PA. I got a few questions but nobody bit, so that is the last damn console I'm taking there. I was also glad I did not take the 1964 Admiral there again, since the guy from Arizona that wanted it (but had no room) last year did not show up this time.   

Then...I saw an article in a 1960 PF reporter on phantom 3rd channel stereophonics, showing the various design approaches by Zenith, Motorola, CM, Webcor and others. RCA's design looked interesting and because my other RCA is straight stereo, I decided to plunge into this. Pulling the tuner and amp out tomorrow.

13
Tube Consoles / Stereophonic 3 channel document uploaded
« on: September 21, 2017, 09:41:47 AM »
An article from a 1960 magazine "PF reporter" on how the various manufacturers achieve the phantom 3rd channel. Since Magnavox did not participate in this development, it is in downloads of other manufacturers.

14
Tube Consoles / High Fidelity document uploaded
« on: September 21, 2017, 08:53:01 AM »
A Motorola Distributor complied a booklet "the growth of sound" on Stereophonic High Fidelity that is a must-read for any tube console or HiFi owner.

If you are logged in as a member, click the "downloads" tab on the very top of the webpage.

15
Other Tube Console Brands / Philco H1619 - small stereo console
« on: September 01, 2017, 11:45:27 AM »
Picked up a small console yesterday from a CL ad that had no picture. Normally I do not bother but the mention of tubes and $20 price had me thinking I should.

The amp has only two single-ended 6AQ5 and two 6AU6 as pentode-connected preamps, but this transformer amp beats many others in this price range that simply have one 12AX7 and two 50C5, with NO transformer. The record changer is a Voice of Music

This 1960 came with documents I plan to upload to the "downloads". The 1960 stereophonic brochure is a great find, because I also have one of the more interesting models (four 6BQ5 and electrostatic) as an unrestored keeper.

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