Is my cab killing monitor chassis'?

[Supernouht]

I have a pair of California Speed 25" sit down cabs. I pulled them out of storage and was getting them set up and linked and they were both working.

They both make a loud "clank" when powered off (which is not uncommon for arcade cabs and I don't know if thatbis relavent) the last time I turned off cab #1 while monitor was working it seemed to be particularly loud. I didn't think much of itbat the time and I don't know ifnit is relavent, but the next time I powered it up it was playing blind with no neck glow.

The cassis is a Neotec nt-2501 and I had a spare nt-2501 that I bought off ebay but had not tested yet. So I installed the ebay chassis and same result, no picture, no neck glow. So just to make sure the problem was the chassis I decided to swap the working chassis from cabinet #2 into cabinet #1. The chassis in #2 is a Sharp Image and after I installed it in cab#1 there was still no neck glow and no image. So then I put the Sharp Image back into cab#2 where it was previously working and now that one also has no neck glow and no image.

Is it possible that cab#1 is somehow killing monitor chassis? The power at the monitor connection measures at 120v and I hooked the crt to my tube rejuvinator and it seems good.
So maybe the ebay chassis was already bad and maybe the Sharp Image chassis from cab #2 just decided to die for no reason right when I installed it in cab#1, but I'd though I'd get some additional opinions.

Now I have another Sharp Image chassis with monitor collapse (but powers on with horizontal white line on screen) that I pulled from another game. I installed this into cab #2 and it powers on and I get a neck glow and a white line. So now my next step would be to install this chassis into cab #1 and see if this chassis gets killed too, but I'm a but hesitant.

Am I missing something, anything I should check that maybe I haven't?

Thanks!

 

[Supernouht]

Some additional info. All the chassis seem to somewhat energize. No clicks and no static coming from the crt or anything but I can measure voltage on the boards when powered up and they do make a quet high pitched hum when they power is connected, and no blown fuses.

Also: Hillarious (and slightly unsettling) that my myspace profile picture from 2007 somehow automatically showed up as my icon here!

 

[nem]

The clank is probably from the force feedback? At least my San Francisco Rush and Hydro Thunder cabs make that clank sound when powered off and it comes from the force feedback.

I don't think your cab is killing chassis. However, are you sure the Sharp Image chassis is compatible with the tube in the Neotec? If the yoke is the wrong spec, you'll blow the HOT on the chassis.

 

[Supernouht]

The clank is probably from the force feedback? At least my San Francisco Rush and Hydro Thunder cabs make that clank sound when powered off and it comes from the force feedback.

I don't think your cab is killing chassis. However, are you sure the Sharp Image chassis is compatible with the tube in the Neotec? If the yoke is the wrong spec, you'll blow the HOT on the chassis.

Oh thanks, no I'm not sure and didn't know that was an issue! I'll check on that.

 

[Supernouht]

Cab#1 with the NeoTec has an A63A26HCX heater voltage is 6.3v and I haven't been able to find a G1 voltage (are there any other critical specs I'm looking for? I have heard that "all" modern 25" monitors were 6.3v heater and 50v G1)

Cab#2 with the Sharp Image chassis is a Zenith A63AGD10X with a 6.3v heater and a 50v G1

Is there another good crt database besides tubular?

Thanks!

 

[nem]

Check the resistance between the yoke windings with a multimeter. There's two windings, one horizontal, one vertical.

 

[Supernouht]

Blowing my HOT sounds like it would be a good thing
Ok so on cab#1 with the neotec/rca tube I have 0.6ohm on the yellow/green wires and cab#2 reads 1.0ohm on the yellow/green. Would that be enough to blow a transistor?

The red/blues are much closer, 6.4ohm on cab#1 and 6.9ohm on cab#2

Edit: I remembered as I was testing this that when I first installed the Sharp Image chassis in the NeoTec cab and powered it on I did initially get a neck glow for about 15 seconds maybe. This seems consistent with a transistor getting hot from overload and blowing out. Less than half an ohm seems like a small difference, but percentage wise that is a 66.6% higher load.

Would a blown HOT result in a no neck glow situation?

Thanks!

 

[nem]

Blown HOT will definitely stop the chassis from working at all.

Horizontal resistance is quite a bit off. You also tried it the worse way around, connecting a chassis expecting a higher resistance to one that is lower.

Try to find the HOT on the Sharp Image chassis. It's going to be a large transistor fixed to a heatsink. You can look up the model numbers. When you find it, see if you get a dead short between the legs.

 

[Supernouht]

Yep, mystery solved! The HOT is shorted across every leg (I didn't unsolder it, just tested in the board). So nothing wrong with the RCA tube, just installed an incompatible chassis, duh!
Well at least I know now and can focus on repairing the chassis' knowing the NeoTec won't fry itself once I repair and reinstall it.

Think that sharp image will work again if I just replace the HOT?

Thanks so much, the monitor coil resistance was not even on my radaras a possible issue!

 

[nem]

Start by replacing the HOT and see where it gets you. It's possible there are more blown components.

 

[Supernouht]

Ok so I was able to find a replacement HOT for the Sharp Image at the local electronics store (yes my town actually still has one!) The original was a D1879 and the replacement they say is an NTE2331.
I also have a spare neotec nt-2501 chassis (not the one from the CA Speed cab) with a bad HOT that I have not been able to find a replacement for, and the store I was at today also didn't have one, but does anyone know (or have a general idea) if this NTE2371/D1879 would be a functional replacement for the NeoTech HOT as well?. The NeoTec HOT is a C5143.

The specs seem fairly similar between the two with most of the power/voltage ratings of the potential replacement just a little higher (which is good right?) except for the Vcbo is 1500v whereas the Neotec part was 1700v.
And it's worth keeping in mind that I did previously blow this same type of transistor that I am thinking of using by hooking it up to the yoke of the neotech monitor that I am thinking of putting said transistor into... So does that answer my question right there, or does the fact that it's actually installed in the NeoTech rather than the Sharp Image make it fine possibly?

I did buy an extra NTE2331 so I could easily install it as a test and if the worst that is likely to happen is the HOT goes out again it might be a worthwhile experiment since I don't have the correct part on hand.

Also 2nd question (and this is just out of curiosity mostly) but hypothetically when I previously hooked up a lower ohm yoke to the Sharp Image Chassis that wanted higher ohm and blew the HOT, If I had placed a resistor in line on the yoke coil to make the ohm reading the same, would that have saved my HOT and would the yoke actually function in that case?

Thanks for your patience to whoever reads this, hopefully these aren't super annoying questions!

 

[Supernouht]

Well I went ahead with the experiment and results where not surprising. I installed the replacement HOT in a known working nt-2501 and the HOT instantly blew on power on. Just sat there chirping. But no damage to the chassis fortunately, I reinstalled the correct HOT and it still works. Oh well only out $10 for the HOT I tested
Now anyone know where I can get a C5143?

Edit:Turns out this transistor is not hard to find, but it's listed as "2SC5143" even though "2S" isn't on the chip. Anyway found one on ebay and it's on the way!