10L43 Predicta no hv
 

I am having trouble with a recapped 10L43 chassis. I should tell you that while I have done a good bit of basic tube repairs...my advanced knowledge of reading waveforms, injecting signals and such is very limited to say the least. I have restored a couple of Admiral combo units but they were just recapping and basic alignment issues. I have met my challenge with this Predicta. Okay.I am at somewhat of a loss to explain the lack of my -45v at pin 5 of the 6dq6. Can someone tell me where that comes from. Is it via the 6cg7, pin6? The K7 netork has been replaced. I have a schematic but am at a dead end here. B+ voltages are good(maybe 10% high), vot, flyback have metered good, and at one point I actually had a modulated raster with good audio though some vertical lin needed tweaking. I have seen Bob Andersons and DaveWM's videos and actually have enough equipment to inject hot and vot signals if I have to. I have never done this before but dont mind learning from the experts out there. FYI I have rechecked the tubes and the crt tests near new....thanks in advance for any support you can give me. Sorry I should have given you this: pin 5 @ 6dq6 measures +6v, pin 6 @ 6cg7 measures 204v.

recheck and report back on all 6GC7 (horz multiplier). do this with the horz out tube out of the socket, you do not want to operate the set with no drive to that tube.

okay Dave...thx for the quick response.

The horiz output tube makes the grid go negative. Very limited operation with the cap off the horizontal output can show some negative if the horizontal oscillator is running. It is best to scope the grid of the horizontal if you can. Check the horizontal phasing (AFC) diodes for leakage. Once in a blue moon I have had them catch me.
On that set, also check your horizontal hold control for opens or leakage. Also, check continuity of the horizontal oscillator coil. A snapped wire will stop the oscillator
Plate resistors of the horizontal driver tube also.

a few things that should be automatic

tube wiggle horz osc, horz out.
tube sub new horz osc, horz out.
voltage checks
resistance checks per chart in sams

voltage and resistance checks are just starting points to narrow down problems like the above mentioned open coils etc.

of course the K network could be the issue, but I prefer to not go there unless pretty sure its the problem, clearly a leaking coupling cap in the network that couples the plate to the grid would cause this problem, but I would scope it to be sure 1st before going thru the effort to make a new network.

one last thing, consider PCB issues, breaks in the traces are not uncommon esp around the horz out due to heat and movement from pulling stuck tubes.


the tube subs are important since they can and do go bad. If you want to check the horz out (no sub) then use the analyst to supple a good grid drive to it. this will clear that tube as the issue.

good point about the pot too, they should be checked (both the hold and range pot) for proper operation. I prefer an analog VOM for this to not only check for continuity but for smooth operation.

would I pull the 6cg7 and inject the grid drive to pin5\6dq6...is that correct

should not need to pull the horz osc, just inject the drive.

there could be a problem though if the coupling cap is leaking, then B+ will get there anyway.

I would try it a and see, just watch for signs of distress, (red plating of horz out).

You could also start with plate drive 1st then work back to grid drive just to make sure no issues anywhere else. the plate drive test the damper/flyback.

I am assuming you watched my video on testing a predicta with the 1076?

oh and yes pin 5 of the 6DQ6 for grid drive.

For simplicity, think of the cathode and grid of the 6DQ6 as a simple diode rectifier. That's what the drive signal "sees". The "diode" can conduct in one direction only, cathode-to-anode. An excess of electrons, which equals a negative charge, appears on the grid. So voltage on the grid ('anode') is negative relative to the cathode.

In early radios, the same principle was called 'grid leak' detection.

okay so I got my 10L43 chassis back from a supposed repair person in Washington State. What a huge mistake. I sent him a chassis with good sound and a partially modulated picture and got back a totally non working chassis with no sound, no hv and a red-plating hot. Some of the sloppiest "repair" work I have ever seen. Okay Dave...I have tube extenders but no scope. You wanted me to take measurements of the 6cg7 with the hot out...is that correct? Looks like the K7 was replaced with what he said was nos...not sure if that was a good idea. I have lifted the board and repaired the "hook and go" repairs. Stand by for 6cg7 measurements...and thanks.

Plenty of people have had trouble with RoXX MaXXXXll, myself included. His history of Predicta and eBay troubles goes back at least as far as 2006 when I won a judgement against him.

Unfortunately eBay still lets him prey on the uninformed, and through his website he finds many more victims.

He's famous for his Predicta "restorations". You send him a chassis, and he replaces only a few capacitors and returns it to you always claiming it works perfectly. You then get the chassis back and find tons of problems including that the chassis just doesn't work. I had this happen twice with him. I was a fool for using him a second time. Then my chassis disappeared, later to be seen on his eBay page "for sale" as a restored chassis.

Somehow he gets away with this over and over, and those victims such as myself that previously mentioned his full name get threats of defamation lawsuits from him and his cronies. We then have to edit him out of our posts.

He likes to call me a liar when talking of him on the forums, but he also knows that I have all the correspondences via eBay and a whole file of his personal emails saved.

If you want a laugh, read the email below that I received from him April 12, 2006. Actually it's probably not funny. It's purely pathetic.

----- Original Message -----
From: "ROXXMXXXXXLL" <[email protected]>
To: "tvXXXXXXXos" <[email protected]>
Sent: Wednesday, April 12, 2006 3:29 AM
Subject: Re: Message LOST CHASSIS

> Dude, i did not take advantage of you.
> Nor were to people on the damned Titanic totally prepared to handle what
> they got thrown into.
> I was good on ALL deals prior to this.
> I sent the damn thing, and ahgain, stressed and in a fucking hurry to
> SATISFY EVERYONE< but myself, forgot to file a DELIVERY CONFIRMATION on the
> box - and of course, the post office lOST it.
> That's what I GUESS has happened.
> Seems people STEAL things - for every time I put a TRACKING CONFIRMATION
> STICKER ON boxes, they never get lost.
> One in 10-15 boxes I send, and usually a Bigger BOX, "without" a
> confirmation of Delivery, gets SNAGGED.
>
> I am FLAT ruined ands broke, unless this LADY forks over 3,000 grand of a
> DOWN on my house - I am moving back to L.A. Area, and will be putting THAT
> addrss on my WEB SITE.
>
> I AM NOT hard to locate - in fact I am too easy to LOCATE.
>
> Either BEFORE or AFTER I get down there, I will take a chuink of the 3000
> grand and PAY EVERYONE I AM IN DEBT TO... other than the God Damned Credit
> Card Companies.... I am getting too old to PAY them back.
>
> By the time they CLEARED my CREDIT REPORTS and I am elgible for clean
> credit, I would be 57 F----g YEARS OLD!!!!
>
> So, at least "people" and such like you WILL be easily PAID OFF.
>
> Sorry for all this happening - it was NEVR intentional - hell, I run a TV
> repair business?
>
> WHY would I PURPOSELY SCREW SOMEONE, who can easily BAD MOUTH ME?
> Easily RUIN my PAYPAL, and EBAY, and etc, and etc, and etc, and etc????????
>
> People,.......???,,, lets all use our HEADS and quit thinking SELFISHLY
> paranoid, as IF "WE" are the only one being screwed?
>
> It's like, WHEN "they" drop that damn BOMB on IRAN soon, even p[eople in
> Tasmania, are going to eat a little crap!!!
>
> So, I lost ( the POST OFICE ) lost another chassis?
>
> This happened 3 weeks ago with another guy.
>
> I had to gut a spare TV and send ANOTHER chassis to him.
>
> That, above, plus all that has happened has added a DOMINO collaspe on me I
> could not stop.
>
> thought I could, but NOOOOOOO,... someone had to fucking STEAL or LOOSE your
> chassis on top of everything else......
>
> So, I give UP.... I am selling this DAMN house DUMP and goiung HOME.
>
> I will take care of you first, before I do.
>
> I have to at least SALVAGE my TV business -
>
> Uncle Sam's SSI and SSEC just does not PAY enough!
>
> ROXX
>
>

I never did receive my money or chassis back from him directly, but did get this nice correspondence from eBay:

----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Friday, April 21, 2006 10:42 PM
Subject: [Norton AntiSpam] Resolution of Buyer Complaint: Case #PP-157-796-431


> Dear JXX XXXXXXg,
>
> We have concluded our investigation into your claim.
>
> We have decided in your favor have recovered funds from the seller.
> We were able to recover $180.00 USD and this amount has been credited to
> you. Please allow five business days for this adjustment to be posted.
>
> If you are due any additional amount from the seller, we will make our best
> effort to recover the balance from the seller.
>
>
> If the seller's account has insufficient funds to complete the refund owed
> to you, please be assured that we will take appropriate action against the
> seller's account, which may include limitation of the seller's account
> privileges.
>

okay Dave here are the 6cg7 reads:
pin 1............196v
pin2.............-.25v
pin3............6.6v
pin4............6.3vac
pin5............0v
pin6............250v
pin7..........-9.5v
pin8............6.7
pin9............0v
hope this helps...btw, I can draw an arc when i lift the hot cap.

ugh...should have asked around here first...well maybe this is salvageable. Should have probes for my scope tomorrow, but I have extremely limited knowledge of it's use. I learn pretty quickly though. I can take hi res pics of the op panel and maybe I can get some support here on learning to use it. Got all this stuff from an old Westinghouse engineer. I can use 80% of it pretty well. I am a little embarrassed about dealing with Ro** but you only get to fool me once. Thanks again in advance.

The 10L43 chassis is a well known item among TV people. If you are patient, the folks in this forum should be able to guide you through the wild, wacky world of Predicta restoration. This article has some notes that may be useful:

http://antiqueradio.org/PhilcoH3412L...Television.htm

When I worked on mine, I found the Philco factory manual on eBay and it was useful to have that in addition to the Sams manual. Each one has a few things that the other lacks. My article includes a few pages from the Philco manual, but I recommend getting the entire thing.

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

thanks Phil....I am quite familiar with your site as well as the restorations performed by Dave, Bob Anderson, and you. While my technical expertise is not near as well honed as some of the experts here...I am no stranger to vintage audio gear and have restored many tube amplifiers. Currently listening to a Scott LK72. This is my second foray into tv restoration...guess I picked a good one. I also have a Holiday chassis that has been recapped as well but no crt for it. I like learning from no bs people. Thank you all in advance and I hope I can contribute to this great gathering of techies. One of my earlier posts has a link to my photobucket page...you can see some of my previous restoration ventures there.

those voltages do not look to far out of line. Next you should check the 6DQ6 (not the plate of course).

you said something about drawing an arc at the plate of the 6DQ6? I have heard of drawing an arc at the plate lead of a 1B3 to see if HV AC is present. I prefer to use a HV prob a the 1B3 DC output (the metal tube socket).

Use a neon bulb held near the plate lead of the 6DQ6 (or anywhere near the fly) it should glow.

regarding predicta repairs,

To do it right requires a lot of hours

pull chassis, can do a through clean up of years of nasty gunk (esp if in a smoky enviroment) just so you can see what you are working on.

remove pcb from chassis

check for defects in traces and tube sockets

replace all film caps

hope the Networks are ok

clean and or replace bad pots

filter caps

and most importantly work around and correct prior hack repairs

There are not a lot of folks I would trust to do it right.

re read your post since the HOT is red plating we can assume no grid drive, but to be sure just get a quick reading there with the HOT in place.

You may end up needing a new HOT when all said and done as red plating can ruin a good tube.

Was there any notes regarding the chassis status after it was returned?

no notes...he called me a couple times telling me he could fix it with a hammer. all the plastic dials were broken into pieces. A few caps were hooked into place because he said they were the wrong values. He replaced K7 but it is an old nos. Pin 6 of the k7 shows correct voltage, not sure if I trust an old nos one. Thx Jim for the pm, if anyone needs any bulk copying done i own a small copier company. I will stick the hot back in and do a quick check. Does the crt and yoke need to be connected...they were for my 6cg7 reads. Don't want to damage the crt as it looks and tests new. I did retest the hot and it is still quite strong.

yes yoke should be connected, its needed for the HV to work.
keep the brightness turned down just in case it comes on strong but does not have vert sweep etc.. to avoid a burn.

They are really not that hard to work on AFTER you get thru the learning curve on how to remove the PCB etc.

I like the modular construction since it takes up a min of bench space.

If it was on my bench I would do another base line test, then if still no go, do the full on pull the pcb up and make sure all caps have been replaced (film type), check traces closely, check tube sockets closely, leave the networks alone for now, try it out again.

On mine I found it fairly easy to remove 4 or 5 wire wraps and then you could unsolder from the stakes. Bob has done more, his technique of complete removal makes access that much easier, just depends on how comfortable you are working on it.

I have worked on a few, the much networks never gave me a problem, but that does not mean they never have issues, I just prefer to see if it will work with them in place before attempting to make my own. Some of them look like they could be checked if need be.

checking the HV with the neon is real quick and a fast test.

okay then

Good News!
 

okay...good news, reasoning that because the grid had ac present I would likely be looking for a shorted cap. Sure enough found defective but NOS sprague .0047 video cathode bypass cap... just because it hasn't been used old is old and I should have checked it before installing it. Replaced cap and hot socket and violla got my -45v at grid and what do you know...full raster with snowy but good picture. Still no sound though...some audio buzzing. No redplating and a good 13.5 kv at anode. Any takers for the sound issue...6bq5 and output tranny test good. This had great audio before my buddy got a hold of it. My guess is that some people are a little timid about lifting that board...ground tabs are pretty fragile and heater grounds are directly connected to three of them. repaired a few foil pops while under there. time for some pizza and a Sam...then a little audio signal tracing. I love this site...pics to follow as soon as i remount the crt in its swivel.

keep at it audio I would start with a new detector tube, check voltages, look for broken tube sockets, check voltage on detector and audio out.

look for open quad coil, they have a pretty sharp peak so may be suffering from screwdriver drift.

"good news" short lived
 

ugh...had a pretty nice picture for about ten minutes...went to start reassembly and lost hv again. completely removed board this time repaired a lot of foil pops and tears, repaired 5 or 6 traces...still no go on hot grid bias. Looks like tube sockets are next...most have broken pins. I need an outlet for 2 octals and 6 nine pin sockets. At least I know all trannys, coils, and crt are good. Alignment looked really good...I think the crt is new. Enough for this weekend though.

where is C42 B+ decoupling cap
 

do all 10L43 chassis have this cap..cant find it on this chassis...it is supposed to be on the terminal strip between the if shield and board by the AOT. The set was working for a short period so I assume it is possible to not have this component.

I presume the C42 is the predicta ref number? I show a C18 .1 uf in that location on the sams and the ones i have worked on have it.

Predicta 17er still no negative bias on hot
 

while I still have not figured this out I have gone through the circuit board as best as I can. I have traced all grounds and appear to be good, all tube sockets meter good too..interestingly enough I have encountered yet another issue I am hoping someone can help me with...the width control seems to be getting very warm. 280v on wiper(vr tests fine) 27 to 50v at other end at hot. I guess without understanding how the basic hot circuit works I was just hoping after going through the board again I would find something obvious. I checked and rechecked my stake connections. Almost impossible to solder without sanding them down. I just don't understand how just moving the chassis a couple inches caused such a huge failure when it had such a nice picture for a few minutes. B+ seems to have jumped about 30v too. I have found another working 10L43 chassis that I am hoping will help me troubleshoot this with my limited knowledge of tv circuits. In the meantime any help would be appreciated.

After reading all of ROXX's crap, I'm amazed he's even heard of Tasmania. As an Australian, I found this quite funny, but I'm glad you won your case.

And good luck with the Predicta whatadish, you'll love it when you find the problem(s) and see that picture for the first time.

Cheers,

Adam

the width pot is a supply to the screen of the horz out.
if its getting hot is may be that the screen is pulling too much current.
If that is the case it may be that the plate of the horz out is not pulling current.
remove the horz out tube and see if you have B+ on the plate lead.
Its ok to check the plate lead IF the horz tube is out of the circuit.
This will check the continuity of the fly windings/damper circuit/choke coil, all of which supply the horz out plate lead. Make sure also that the damper filament is lighting, I had a predicta that would loose its HV unless I pressed on the damper tube sideways, turned out to be a bad filament ground stake that only effected the damper tube.

remember do NOT check the horz out plate lead with the tube installed, the strong pulses of a working horz sweep circuit could destroy a meter.

this is way off, should be about 175v at the screen.

sounds like you have lost the B+ to the plate lead of the Horz out (and the screen is drawing all the tube current).

see my prior post.

Came here looking for some tips and techniques for fixing up my 10L43. Lots of good information and thanks Phil for your detailed restoration blurb on your site. But I just have to say how appalled I was reading that email from RoXX--etc. etc. It's well beyond belief.