Motorola TS-14 - Videokarma.org TV - Video

DaveWM · #1 02-27-2010, 12:09 AM

nice looking set, pics coming.

I checked the various coils for continuity, looks good. Started replacing caps, yikes, must be 35+ not counting the doublers or filter caps.

I only have about 4 more to go, but its getting late so will knock off and try to finish up over the weekend. I have a good 10BP4 for it.

I am going to bone saw the cans from the top fo the chassis and use radial lead electros. It has twin SE rectifiers for the doubler circuit. I will leave them alone at least for the power up to see where the B+ is.

there is a fusister but I dont know the value (unmarked), it looks ok but I think its open, I need to check it again. I figured they would look burned or distressed some way if they were bad.

The set seems pretty modern in its use of tubes and Low voltage ps for a 1949, I did not expect so many mini tubes and the doubler circuit.

bandersen · #2 02-27-2010, 12:27 AM

Can't wait to set it up and running. I think the TS-14 was a nice evolution from the series filament TS-4 chassis.
I see a 7.5 ohm resistor between the AC line and 140 uF doubler cap in my schematic. Maybe that's your fusister ?

DaveWM · #3 02-27-2010, 12:35 AM

Charlie is working on getting a scan of the schematic for me.

Its a nice looking cabinet, I found it odd that it had all those mini tubes, the doubler and a then a field coil speaker. the mix of the new and the old.

the cabinet is in very nice shape, so I will not have to do anything to it.

bandersen · #4 02-27-2010, 12:53 AM

Cool. Yeah, early Motorola sets were interesting designs.
I have a Motorola 12K2 that uses the same chassis with a 12LP4 tube. My cabinet is riddled with wood bore holes though. What model is your set ?

DaveWM · #5 02-27-2010, 01:33 AM

10VT24R

ok I see, so this is a string filament set? the PT seemed small. plus there is some funky looking open transformer that I am not sure what ist function is.

So I guess I need an isolation tranny when working on this?

bandersen · #6 02-27-2010, 02:04 AM

Ah, I haven't seen that model before.

Sort of. The filaments in this set are parallel off that small transformer

The transformer is smaller because the B+ is derived from the voltage doubler off the AC line. That's what I meant by the design evolution.

I'd still use an isolation transformer for safety, but the filaments aren't subject to burning out by the surge when it's turned on.

Phil Nelson · #7 02-27-2010, 07:49 AM

Here's a scan of the 12K2 schematic, if that's of any use.

http://antiqueradio.org/art/temp/Mot...2Schematic.jpg

A visitor to my website is working on one and emailed a couple of questions to me.

Phil Nelson

DaveWM · #8 02-27-2010, 04:13 PM

Full recap done, fire it up, audio, cool, but nada on HV. mess around for a bit, found a unsolder floating ground wire on the HOT term strip, argh. It was one that had a lot of caps on it and I must have missed resoldering it. got that and bingo raster, and a what looks like an attempt at a pic. Change channels, bingo again a PERFECT pic but no sound (well lots of buzz but no sound).

So I guess there is an adjustment issue, not sure if this is a case for alignment of the IF or an adjustment to the discriminator circuit.

I promise pics coming kid are home so I will get them to find the camera.

DaveWM · #9 02-27-2010, 05:38 PM

here you go.

Sound is acting up, when you 1st turn it on its fine, then all of a sudden it snaps into pure sync buzz sound. I will try letting it cool down completely and see how long it takes to snap out of audio again.

At 1st I thought it was a channel issue since I had sound on one channel and video on another, now I realize what happned was I just lost the sound when I changed the channel, changing back did not bring the sound back.

I have another tv that is sorta the same deal but in that case I get the loud buzz when the set 1st comes on, and after it warms up for about 15 seconds the loud buzz goes away and you get perfect audio. Happens everytime. I never tried short cycling the on off to see what would happen

How do you like that speaker, field coil job looks brand new...

DaveWM · #10 02-28-2010, 05:36 PM

got the sound worked out, turned out to just be the 6AL5 dual diode in the ratio detector, duh, I can't believe I did not catch that early on.

I plan to try out a few other 10bp4's that I have laying around just to see how they look, compared to how they read on the CRT checker.

Anybody have a scan of the TS-14, Charlie looked but it was missing from the folder. The schematic that Phil attached was close but had some differences. I am also hoping to find a sams with resistance and voltages.

DaveWM · #11 02-28-2010, 08:21 PM

Got it back in the cabinet in time for Mike Hammer...

just have to get the knobs on it and find a suitable viewing location.

bandersen · #12 02-28-2010, 11:21 PM

Cool set - that's such a funky cabinet design. I think I have the TS-14 info you need. I'll take a look tomorrow.

bandersen · #13 03-01-2010, 05:35 PM

I've scanned schematics for the TS-14 and TS-14A/B from my Wallace's Telaide. Some voltages are indicated throughout. I hope this helps.

http://www.bobandersen.com/images/schematics/motorola/

DaveWM · #14 03-01-2010, 06:09 PM

Thats it, thanks!

I seem to have an audio issue, lots of sync buzz and the overall audio out is low. I am thinking it has to be L-18, since the composite signal is strong (plenty of contract and a solid lock) and IF tubes are fine. I suppose it could be the ratio detector but I would rather not mess with that.

DaveWM · #15 03-01-2010, 06:13 PM

follow up, I am thinking that maybe the signal is not strong enough for the limiter to clip so I am getting the sync buzz and other AM stuff. Not too sure about that, just thinking out loud.