Wells Gardener 19V1001

[Ronnie Dent]

I recapped this monitor last year and replaced a few variable resistors as they were shot only cap not done was the
the 4 in 1 filter cap and as the screen was
vibrating violently I replaced that with 4 separate caps each a bit
higher in uf than the original, that went well but I now have a wobble
across the screen and some blooming, so I checked the B+ but
I'm getting 95vdc! And the pot has no affect on that? It is the big pot
near the test point I think? Even if it's not the other one at the
opposite corner does nothing either? No mad rush as the boards are away
to be repaired but would like to have it ready.

The 4 in one values were

800uf now 1000uf
200uf now 220uf
200uf now 220uf
20uf now 22uf

all higher rated voltage the the old one's

Cheers Ronnie

 

[jengineer]

the caps need to be the exact microfarad, the voltage can be higher but the uf has to be the exact same

unless this is a different situation?

jengineer2015-08-10 09:59:42

 

[Ronnie Dent]

the caps need to be the exact microfarad, the voltage can be higher but the uf has to be the exact same

unless this is a different situation?

Thanks, I did read a few forums prior to doing this and most said they were just filter caps so higher would be okay but maybe the 1000uf is overkill as it's directly attached to the B+ rail, I should have checked the voltage prior to working on it!

Thanks Ronnie

 

[Ronnie Dent]

The caps are c101 A,B,C and D on the schems below, the only thing I'm not sure about is C104 a small disc cap which the legs were too short so I replaced it with a 103 disc cap? maybe that's the issue?

Thanks Ronnie

 

[obcd]

C101 A B and C are indeed filter cabs. The fact their value is a little higher than original shouldn't matter. (I can't seem to find C101D on that piece of schematic.) C104 likely isn't the cause of your problem. What you could try is place your meter in the AC position and check if you have a ripple on your B+ voltage. Some meters are capable to measure only the AC component of the voltage, others are not capable. Basically, a scope is what you really need for this. R212 should adjust the B+ voltage. If it doesn't work you have a fault around Q101 and Q102 or Q204. I would surely check Q101 for a collector emitter short in this case.

 

[Ronnie Dent]

C101 A B and C are indeed filter cabs. The fact their value is a little higher than original shouldn't matter. (I can't seem to find C101D on that piece of schematic.) C104 likely isn't the cause of your problem. What you could try is place your meter in the AC position and check if you have a ripple on your B+ voltage. Some meters are capable to measure only the AC component of the voltage, others are not capable. Basically, a scope is what you really need for this. R212 should adjust the B+ voltage. If it doesn't work you have a fault around Q101 and Q102 or Q204. I would surely check Q101 for a collector emitter short in this case.

Thank you for the advice, it might be C101 then A B C? will have a look, if it's just C101 then it should be 20uf 200v

My meter is a Fluke so it's fairly accurate, will check for AC ripple, I also have a complete untested chassis so I swapped Q101 out last night but no change, will need to pull the chassis and double check my work. Am I safe to power the chassis on the bench with no crt to check voltages?

Thanks Ronnie

 

[Ronnie Dent]

The AC reading across the B+ is 0.856?

Thanks Ronnie

 

[obcd]

Is the B+ adjustable with R212? The schematics show a B+ voltage of 75V. If yours is 95V, it's not good and it might kill the HOT. Maybe the schematics are from a slightly different chassis with a smaller picture tube? That could explain the lower B+ voltage.

If you run the chassis without a tube, be carefull with the anode cap as it has very high voltages (from 10 - 30000V) I read about people putting it in a glass jam pot. When I repair monitor chassis, I usually disconnect the B+ from the horizontally drive section and load the supply with a 25 or 40W light bulb. You can't check all faults like that, but for supply faults it's good enough. Hantarex chassis even turn off the horizontal section automatically if you disconnect the deflection coil plug.

So basically, I have no idea if it's safe to run without tube and deflection coil connected as I have never done it.

 

[obcd]

One more question. Did you start having the wobble after you replaced C101 with the 4 capacitors or did it work well for a while after you did that? Maybe you replaced C101 in an attempt to get rid of the wobble?

 

[Ronnie Dent]

One more question. Did you start having the wobble after you replaced C101 with the 4 capacitors or did it work well for a while after you did that? Maybe you replaced C101 in an attempt to get rid of the wobble?

Thanks, no the B+ does not change with moving the pot. this is an old monochrome chassis and the B+ should only be 75vdc, I pulled the chassis out and checked Q101 it reads as good, also double checked my work it all seems good, but Q102 is reading low ohms from ground to both it's pins either way? it's a BU207, it also reads the same on the untested chassis?

The reason I changed C101 was I had violent shake of the picture allover! since changed C101 I have the wobble or like a slow wave across the screen and the picture expands and shrinks slightly? I have a BU208A which I think is a compatible replacement for Q102?

Thanks Ronnie
Ronnie Dent2015-08-10 11:46:08

 

[Ronnie Dent]

The full manual can be found here

http://pdf.textfiles.com/manuals/ARCADE/S-Z/Wells-Gardner%2019V1001%2019V1003%20%2819in%20and%2023in%20B&W%29%20%5BServ%20&%20Parts%5D%20%5BEnglish%5D.pdf

Thanks Ronnie

 

[obcd]

Normally Q101 should be a big (mounted on a heatsinc) transistor and Q102 should be a smaller one (like a TO220 housing). According to the schematics, Q101 is a 2N5632 and Q102 is a MPSA06.

Maybe the BU207 was a replacement, but are you sure it's a replacement of Q102 and not Q101?

In the first pages of the manual, you have a separate schematic of the power supply section and everything that is involved in it. If you manage to fix the 75V (and the fact it should be adjustable), I am pretty sure the wobble will be fixed with it as well. Best methods to measure the transistors is by desoldering at least 2 pins so that no other stuff can influence your (ohmic) measurement. Collector (most of the time housing) and emitter should measure infinitive. Base - emitter should measure 0.5 - 0.7 in one direction and infinitive in the other. Base collector should be nearly the same.

 

[Ronnie Dent]

Yes Q101 is 2N5632 and Q102 is a BU207 on both chassis, and they are both T0220 housings, easy to remove and check with meter I'm guessing they will read good out of the chassis but will check.

I remember last year I had the chassis out to clean and recap the pcb and I was able to adjust the B+ no problem to the correct volts, not sure what has went wrong? surely can't be much?

Thanks Ronnie

 

[Ronnie Dent]

Sorry I'm getting Q102 mixed up with Q103! my bad, need to find Q102 then, Q103 is the BU207 width amplifier I think, sorry!

Ronnie

 

[Ronnie Dent]

Right found Q102 it's not on a heatsink or anything it's marked GE86X65-1 from it's tab to right pin it reads short but so does the other chassis as well as the other same device on the pcb so I think that's right? and i desoldered it's 2 legs, otherwise it reads fine over it's 3 legs. not sure what's going on with it?

Thanks Ronnie

Scrub that! wrong device again! Q102 is a small transistor no shorts on it but need to check if it's open, think I'm going daft!
Ronnie Dent2015-08-10 14:13:27

 

[Ronnie Dent]

Q102 seems to read good and Q101 removed also looks fine but getting many k's of ohms when it's conducting for instance C to B reads 283k E to B 297K but no shorts in either device?

Thanks Ronnie

 

[Ronnie Dent]

Forgot I had one of those kit self build testers both Q101 and 102 read good in the tester and it recognizes there polarity. I tempted to test the other chassis but I suspect I bought it as faulty!

Cheers Ronnie

 

[Ronnie Dent]

I fitted the other chassis, the B+ is only 37v and those big wirewound resistors are heating up that was obvious when I looked at them earlier that they had at some point been cooking, so that has another B+ fault!

Cheers Ronnie

 

[obcd]

What voltage are you measuring on the base of Q 102? The voltage on ZD201 (the zener) is interesting to know as well.

 

[Ronnie Dent]

What voltage are you measuring on the base of Q 102? The voltage on ZD201 (the zener) is interesting to know as well.

It's almost impossible to get at these to take voltages when it's all connected up! if I could figure out how to load the B+ to a lamp and isolate from the flyback I could do all that on the bench as the transformer has a jumper for 220v feed rather than the 120v it gets in the machine, I'm going to order some new Q101's think it cross references with a 2N3773 instead of the 2N5632 which are harder to find, I also read this on the DLF forum for a similar B+ issue-

"Well, I did a little work on the game yesterday and I fixed the issue.

I
tested the B+ and it was around 87V. It's supposed to be 75v. Adjusting
the pot would not make it lower. So, I replaced the voltage regulator
transistor and it's all fixed!

That was easy.

Now
I need help adjusting the picture. I can't get the picture down far
enough to line-up with the blue line for the paddle. If I move it to far
down the left side curls. What is the horizontal oscillator adjustment
for? Is that horizontal width? I need to find a horizontal center
adjustment (to the bring the picture down on the vertical monitor) and I
don't see one."