1949? Motorola 10VT24R, TS-14B chassis
 

Hey ya'll, It's been a little while. Well I thought I was going to be getting to my Zenith SC, but the space I had reserved for pulling it apart in is not available anymore at the moment, and like I said before, I'm not dragging it down to the basement. For now, It'll wait.:boring:

Anyway's, after recapping some radio's, I've decided to get into this set. It's allready got an issue. Well, what's new about that.:grumpy:
So far, I've replaced all the Electrolytic caps, some paper that looked suspicious, and some that were clustered together around the suspicious one's since I was on a role... I have more to go. I also allready swapped the celenium's for 1N4007 diode's.
Unfortunatly I dont have a schematic to go by for this one. It's on ETF's site but it's too hard to read...http://www.earlytelevision.org/pdf/m...4_manual.pdfSo i've been going with what's in the set since it was complete and didn't look burnt.

Well, I tried a power up and... blew an E-cap:mad::whip: It was only at 30V!...
I also found that none of the tubes had lit up(all are good) and I had really heated up another e-cap. Both of these caps are connected to the diode's. The diodes are wired in the same as the celeniums were. positive-negative wise. I never added any resistors too them. (I don't know if they need them or not.) The cap that blew was a replacement for 140mfd/150v. I had 147mf/160v in place and it heated the 100mfd/300v cap up. Nothing that I could see was shorted out on another component, so why would it do this with only 30v being introduced into the set???

some pics.
Note: I know my e-caps look like a mess, but nothing is touching what it shouldn't be. I also have pictures of what I beleive is a capacitor. Is that the value on the backside or a part# that looks like a cap value? I havn't come across capacitors that look like that one yet.

Well usually for a cap to blow like that the polarity has to be backwards.

From what I can see in your picture you have the positive of the Diode going to the chassis ground and the negative going to the positive of the cap?

The angle of that photo is a little misleading.
The one that blew(147/160v) is connected at the positive and negative of the 2 diode's. The positive of one diode then goes to the 100mfd cap+ and the negative of the other goes to the 2nd e-cap can ground. (I kept the cans as the ground points, and only disconected the positives of them.)

Quick question, the negative of the diode's is the side with the line right?

No, the Positive of the Diode is the end with the line.

That one marked .047 400 is a cap, a paper type, not electrolytic. .047 Micro farads at 400 volts, a higher voltage can be used but the .047 must stay the same.

The diode conducts when the end with the line is negative.

This means that when used as a rectifier, the end with the line
is the plus end. That obvious diode has the correct end to ground.

I do suggest that if you leave that mess as-is, use plenty of
vinyl tape! I've been known to do that. Its not OK, well it IS perfectly OK
electrically, just leads to nasty comments on Videokarma.

The appearance of a paper cap is not a reliable guide to condition. It can look perfect on the outside, yet leak like crazy when you apply the operating voltage.

This article has basic information about identifying old capacitors and choosing replacements:

http://antiqueradio.org/recap.htm

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I can't find the schematic anywhere, but if the B+ supply uses a standard doubler circuit, it should be one of the two configurations shown here..
http://www.electronic-circuits-for-h...-two-diode.php
The banded end of the Si diode denotes the cathode. Seleneums frequently had a '+' sign denoting the cathode, which is counterintuitive as hell. But that was the convention.

hi, Check front cover of the Motorola manual you will see that it is for chassis,TS-14,TS-23 and TS-52. Photofact for all three is 92-4. ETM does have a scan of that photofact. All the best, tom.j.fla

Thanks guy's for the info about the diodes. I didn't realize that when used as rectifiers that ya essentially swap there polarities. I had them in backwards for that funtion.
Hey Phil, when I talked about the suspicious caps, they looked plain bad. Side popping out if the one, another had the lead pop off when moved,yadayadyada. hey Tom, I'll have to look that up on a PC. It doesn't seem to want to work on the IPod touch.

Anyway's I put new E cap in place of the blown 147/160v unit. Also checked the diodes and they test good. I rewired them how they should be.
Should I replace the 100mfd cap as well? It got hot but didn't ooze it's guts.
I decided to try another power up. Had the dim bulb tester on it this time. Everything OK, so I upped the power and got a raster. In the form of a 1.5 inch horizontal line on the screen. I couldnt get it to fill the screen.

Well, I replaced most of the paper caps. Still have 3 bumble bees by the gang of e-caps. I decided to power it up again. Same basic response, except I seem to have better sound now,more shush since it has no incoming signal. No real improvement in the image. Still can't get it to fill the screen. My vert output tube is good. It's also wavy (like 60hz interferance) so Mabey that 100mfd is f'd up. I also noticed something I find very odd. The picture is it's brightest at about 85volts. When raised to 110v, the picture goes very dim. I have no clue what the deal with that is!?

That's where I'm at so far. Whatcha y'all think?...

I think that you should really get the rest of the caps replaced before you go any further. Replacing the seleniums with diodes but leaving *any* capacitors un-replaced in a set of this age is doing it backwards IMO.

Be aware that I worked on my TS-14 for sync troubles for a long time and got nowhere! I had replaced the seleniums with 1N4007 diodes and the B+ was too high. I added resistance in line with the diodes and got the B+ where it should be and the sync was fine. Replace the caps in the horizontal oscillator stage. If there are leaky ones the set goes nuts! Other than that, these are reliable sets and have a great picture!

I would replace any electrolytic cap that got reverse voltage, especially if it heated up.... and get those darn bumble bee caps out of there ASAP.

jr

Generally you have to add resistance to the diodes when doing a selenium replacement as a rule. Only exception seem to be 7" electrostatic sets. You can calculate the proper resistance (or at least ballpark it) by looking up the specs of the selenium in the sams.

But jr_tech is right. You're asking for trouble leaving those bumblebees in there. I'm by no means the last word on TV restoration, but it's been my experience that you can't leave any of that stuff in there and expect the set to work long term.

As a rule if a cap gets warm or hot in operation (assuming a power tube is not really close and heating it up) THEN IT IS A BAD CAP, if you wait until they blow their guts odds are other possibly unobtainium parts are going to be killed by them.

Ok, the bumble bees are gone,(There was no plan to keep them) and so is that 100mfd E-cap. That cap's replacement looks worse now(3capscombined) but at least I don't have to worry about it. The "general" recap seems to be complete. No more old papers(bb,or those plastic ones) and no old E-caps.

Hey Zenith26kc20, Do ya remember what the ratings of your resistors were? I'm not sure how to figure it.
Kamakiri- I saw in the Sams mentioned above http://www.earlytelevision.org/pdf/M...-Sams-92-4.pdf and the only spec is the current rating, which is .225A for both. I don't know what to do with that info.

After working more this evening, I powered it up again. All is the same...:no: Well, at least it seems stable. Nothing burned up or changed in the 15 minute long power up.:yes:
I'm still dumbfounded with it losing brightness when the power is raised to line voltage. And I can't get it to fill the majority of the screen. Only have a 1.5"-2" horizontal line. I noticed if I turn the horiz hold more than 1/3 counter clockwise this thing just SQUEALS. I also notice that if I messed with the vert.lin or size(cant remember which), and put the control in the middle the screen would bounce into the thin horizontal line, then it will go back to the 1.5" line without changing the control...hmmm this thing sure is strange:scratch2:

Thats where Im at so far...
heres a picture!!!

Did you try turning down the brightness at line voltage? What may be happening is when the brightness comes on turned up full it may be pulling the high voltage down which in turn, kills the brightness.

There's a bit of keystone in that raster, possibly a sign of a bad yoke but more likely something wonky in the vertical circuit.

The horizontal squealing is caused by it running way off frequency, you may need to adjust the frequency coil, or possibly you have a cap that's the wrong value in the horiz oscillator circuit (which could also bring down the high voltage and brightness).

On the vertical circuit make sure the tube is good, the resistors are in tolerance, the pots are clean/not open, and check voltages on the vertical tubes.

If that fails connect the yoke or primary of the vertical output transformer to a variac (make sure it is disconnected from the set before connecting to the variac) and slowly turn it up while watching for more deflection. If you don't get more deflection from that then your yoke or vert transformer is bad (which one can be determined by the connection point).

To add to Eric's point if the H osc. is out of tune it can cause poor HV regulation and even cause the HV to drop out. If you have a scope, connect it to a video source (like a DVD player), and measure the horizontal period by looking for the synch pulse, then with the horizontal settings of the scope unchanged connect the scope to the set's H osc. and tune the osc till the width of the osc wave form is as close as you can get it to the one you measured on the composite video....I've done this on sets with pure unobtanium flys before plugging the output tube in as a safety precaution, and it has worked.

In responce to Eric's post. My computer is being very slow tonight.

I did not turn it down. I left it alone durring. I havn't had it set at max though. I don't want to take the chance of burning the crt.

I know that yoke is stuck on the crt. When I tried pulling the crt off, it wouldnt let it move far.... I didn't want to push my limits so i just tightened everything back up and left it together. I also dont think that thingamajig behind the yoke is original. Looks different than the images on the manuals

in responce to Electronic M...damn slow ass computer

Tubes are good, pins are clean, I cleaned all the pots but still have yet to check them. I still need to check resistors and voltage too.

That sounds like an interesting test...

Unfortunatly I dont have a scope....or much of any actual test equipment other than my analog multi meter and my tube tester.

If the yoke is an "iron wire" type, the iron wire making up the core will make the windings shrink and get stuck to the neck of the picture tube. I fought with my Admiral and ended up losing the vacuum in the CRT when I accidently pulled the CRT socket off when I tried to put the yoke over it. I got a replacement that had an iron wire yoke (stuck also) and unwound the wire and got it off. I also had to get a replacement yoke for the admiral. Be careful and if you don't have to, leave the CRT/yoke alone for now. If the variac test shows the yoke bad, you'll have to take it apart to get it off.
The resistors were around 22 ohm 5 watt. Check the B+ after you install them. It looks like you have a good number of bad capacitors in the set. I completely recapped mine before I started to troubleshoot.

Good thing I never pulled it off then. I wanted to for the recap. Oh and yes, it's fully recapped. I really hope it didn't look THAT bad to ya...to make ya think I've done nothing in regard to recapping. Thanks for giving me a value to look for in my resistor stash.

While poking around it last night, I noticed that there are 2 oddball looking resistors under the yoke with the wires. It looked like they were supposed to be connected to each other on one side (and go in) I couldn't see where the leads led to on the other end. Well the one had broke off on one side.(where they were connected to each other). I'm going to resolder that connection together and see what it does.

Also, anymore tips on testing the yoke/vert transformer? If I test the yoke, do I hook the wires to the +&- of the variac? Or just the positive and other side of the yoke's vert. to a ground? Idk. If I test the vert. output trans I hook the primary to the + of the variav but where do I go with the neg? Honestly I don't know much about this test, still learning as I go with these TV's...Well even with the radio's!

You can use an old line cord to plug into the variac. I put alligator clips on the wire ends. If you remove the B+ from the vertical transformer (usually the red wire coming from the power supply) and connect the variac from the transformer wire going to the tube socket (plate of the tube) with the set powered up, go from zero volts on the variac up slowly. You should get deflection as you increase the voltage from the variac. If the keystone still exists, the yoke is probably bad. This set has a "hot" chassis, be very careful with the variac connections. Do not let them contact the chassis. It looks like it has a power transformer but the transformer is filament only. The B+ comes from a voltage doubler.

according to the schematic, the vertical windings of the yoke have 100 ohm resistors across each winding. If the transformer has never been changed, the wires you would put the variac across are red and blue.

It may be easier to visualize when you compare the diode to a vacuum tube rectifier. The end of the diode with the band is the cathode, the other end is the "plate". The cathode of the vacuum tube rectifier is the side that B+ comes from. As seen from the AC source, the power transformer secondary, there are two cathodes in series. One of those cathodes is the rectifier, the other is one or more cathodes of the various tubes doing the audio amps, IF amps, vertical or horiz outputs, and such.

Confusingly, some selenium rectifiers had "+" symbols next to their cathodes. As if to say "Connect this side to your B+ filter caps".

Well, who's got an extra yoke they want to sell....

Thanks for "spelling out" that test procedure for me Zenith26kc20. I appreciate that.

Well I wired in the resistors on the diodes and also disconnect that vert. out. transformer, and hooked it to the variac. I powered the set up, slowly turned the brightness up till I could see a line, then flipped on the variac. Well, when I started applying voltage I noticed the wierd line on the right popped on the screen and(I didn't know how high I should go) I eventually went up to 90 volts with it only growing to about the same size it always has. I didn't want to burn the trans up so I stopped at that 90 and just shut down.

Oh- some good news that I forgot to mention a little while back.
It seems the tuner's at least fine and signal gets where it should. I hooked an old videogame to it just to see what it'd do, and got good sound, and video in what I do have for a picture!

Well, what do y'all think? Did I go high enough with the variac, not high enough?... Where can I get another yoke that would match or just work correctly? Would it be hard to rewind the windings on the yoke? (I've never done anything like that before). Where should I go from here?... Should I just put it back together and just say "the hell with it"?
IDK........

:nutz:UPDATE!!!

I got a new yoke for it. I had to murder the old one to get it off. That thing was also pretty rusty inside as well... Now its extra scrap metal.

Got the new yoke on and put it all back together. Figured out how to hook it up correctly, and got that all done and wholla! I've got a full size rastor.:D

Now... I noticed that it seems to have video sync issues. I'm going to need some help with figuring this out. Other than that, all seems well with it, nice and stable.

I've got the set attached to my SNES in the pic.

Can you get the horizontal bar to roll both ways (up and down) with the vertical hold control? Can you get the horizontal to sync even for a moment by with the horizontal hold control? If the answer to either of those is not then the circuit associated with the control needs more work and or adjustment. If the answer to both is yes go after the AGC and synch seperator stages....Try adjusting the AGC if it synchs with good contrast your good if all it does is change the video level leave it at a setting that gives reasonable video and move on to the synch sep (check it's resistors).

The vertical will need to have it's resistors checked if it can't be rolled both ways with the hold control. If the horizontal can't be flopped both ways first try adjusting the slugs of the osc. transformer (assuming it is a synchroguide circuit)....Get it in synch, and then use a scope to get the peak and hump of the waveform roughly the same height (crucial for stability).....If the osc. can't be adjusted for sync. then check all the resistors in the horizontal.

I can get it to roll either way, and stabalize with the vert.hold control. What you see in the pic though, is the best the horizontal will sync. It'll stay like that,(won't bounce around) but I can't get it to adjust into 1 full image. and I cannot mess with the hh control much, because it'll squeel like crazy if turned more that 1/4 counterclockwize. I always slam it back to the safe range, then because I don't know if that sound equals harm or if it's just emitting the sound... I'll have to check some stuff around there like you suggest.

I dont think my set has AGC...I'll check around the sync seperator some. Honestly I havn't done much 'checking of resistor's.

Should I mess with the osc. trans. if I don't have a scope?

You need to find the horizontal frequency coil and adjust that, the Horizontal Hold control Pot is just a coarse adjustment, there should be a coil somewhere on the chassis connected to the oscillator tube that will bring it into range.

If you have vertical sync. and can't get the horizontal to sync or even a single sideways rolling image, then the sync sep. etc are probably fine.

That osc. squeal means the horizontal osc. frequency is WAY off. Check resistors in the osc. circuit and change any mica caps in the horizontal. If that fails adjust the osc. transformer....There will likely be a O-scope-less procedure in the Sam's for the set for adjusting the osc transformer. It is workable to do it that way, but using a scope will make it much quicker and easier.

If you plan to continue to do TV work, an oscilloscope is going to be necessary eventually or at it will least save you hours of confusion.

Welp, a big thanks to you guy's!!!:banana:

I checked over a bunch of resistors in that circut. Most have drifted up some. I'll probably replace a good number, before i'm all done as they are right above the 20% tolerance.
Also printed out the schematic and had that in front of me. I'm surprised at how many caps were (previously) replaced with values that didn't match.(the schematic)
I don't know if I should switch my replacement's now that are in there, or just leave it as is(I didn't use the schematic to recap, just went by what was inside)

Anyway's I found that adjustment coil, and decided to see what I could do. After several turns clockwise, I could see the images blocked up on top of each other. Kept going and it locked into one full image!:D I then dialed it in with the horiz. hold control and centered it in the control.
Wow, I got a pretty damn good looking picture:cool:....but IT's UPSIDE DOWN!!!lol:wtf: Yoke is positioned correctly...do I have the vertical connections on the yoke miswired??
I also still need to center the picture as well. I notice that it's got a little wave as well and slight geometry issues... And an issue with the best sound and best image not being together with the fine tuning control. Has some buzz and gets quiet when adjusted to best image, and a cruddy looking image when it's adjusted to lowdest sound.

Well I've still got more ahead to do, but that's where i'm at for now.:headscrat

Now some pictures!!

And the horizontal connections.

Reverse the vertical wires, and then independently reverse the horizontal wires. Don't cross connect the vert and horiz. Best do the vertical, then test the set, then assuming success (image will look right side up, but mirror reversed) then do the horiz.

Or rotate the yoke so it becomes "upsidedown".

This is important advise for restorers: If a set does not look to have had any hack repairs or work done on it, and a part or parts don't match the schematic GO WITH THE WAY THE SET IS WIRED AND THE PART VALUES IN IT first. Many chassis went through several production changes, not all are documented and there is no way to tell if the schematic is the worse or better version, and that is assuming there are no mistakes in your schematic (I've had mistakes in service literature screw me up a few times now). The only times to make a set match the schematic are in the case of fixing untrustworthy hack-repairman workmanship, and in the case of testing and replacing all parts in a misfunctioning circuit and not curing the issue.....At that point if the schematic shows a different way of making the circuit it is worth a try, BUT make notes of how it was to go back to.....This advice applies to all tube era products IMHO.

Glad to see you got it working (sort of)! Once you get the picture flipped right side up, it looks like you're home free. For your next restoration, take a look at Phil's capacitor replacing page.

http://antiqueradio.org/recap.htm

Towards the bottom, it shows how to restuff an electrolytic can. It takes a little more work, but it's a tidy method. I usually cut the old can open with a pipe cutter and dig the guts out. Then, I just use radial lead electrolytics (the smallest diameter available), drill holes at the bottom of the can for the leads, and put the whole can back in.

Sorry I'm a little late getting to the thread.

On most can caps I've found using a cork screw to remove the old guts (once the can is open or cut off) is a very effective method. :drunk:

Hey guy's. Sorry for dissapearing... been a little busy with other shtuff. Anyway's I got the screen corrected. After I saw wa2ise's post,(on the 30th) I swapped the wires around and the screen looked right. Still have issues to correct, but I decided to play some snes. Nice and stable for the hour, everthing seemed good other than the filiment trans. got real warm. Not hot, but quiet warm. Also had some vertical lines appear on the screen after 10 minutes. Not sharp lines but just 6 or so about an inch apart across the screen that were slightly brighter than the image itself.

Well, I noticed something that I made a mistake with... I had the set running at around 85-90volts... Well when I upped it, (115v) I noticed that the screen got to a better size-actually got a little too big for the 10 inch crt... and the brightness took a dip, like it did before. (started going darker above 90v.) I had to turn that up a little more too look satisfactory. Also noticed the screen geometry issues a little more. T1 (fil.trans.) also now got HOT. Not burning hot but, what I would call hot for a tranformer operating temp.
I haven't touched the set now in a week.

Hey Niko, yea what I did was kind of sloppy. I may still restuff the cans later. I'd rather worry about getting everything good to go, first though.

No pics this time.. that's where its all at.:boring:

Well, I swapped a few resistors and also replaced 2 caps that looked like Mica's but were rated high in the schematic. No real changes that I noticed. Also noticed that the vertical lines appear now right at start up. I need to get a photo for y'all.

Update
 

Well, i've got this one back in front of me. I ended up putting it back together and out of the way for whatever reason, that im not sure of anymore...Either way, it's been too long.

Anyway's, when I got it back out, I found I have more issues than before. For one, I lost my High Voltage... or at least what is required to get a rastor. I found that a resistor on one of the 1N4007 diode's went open. For now I just took that resistor out of circuit. It's not absolutly necessary right now.

Got HV back, but I have no vertical deflection...Just a horizontal line. That one I can't figure out. I replaced some resistors in the vert circuits, but still have no vertical. Checked a number of other's and cant find any way out or shorted. My tubes are good, and I had it before I put the set away.
Should I swap some of the previously changed caps? I rechecked the vert. transformer and that's still good. What do any of y'all think???