Is this cap replacement too small

[TinCanAlley]

While this isn't TV related, it is CRT related.

I've been working on a TRS-80 Model 4 power supply and after recapping and double checking, I still managed to mess it up by putting a capacitor in backwards. Upon firing up the unit, it all seemed to go well, but when I accessed the disk drive, the screen dimmed and shrank with a pfft sound and magic smoke came out of the upper left. This couldn't be the power supply as it is centrally located. It had the be the video board, so I removed it and found a tantalum with a nice hole in it. I figured that since I had to replace that, I might as well tackle all the electrolytics and order all noted values. The caps arrived yesterday, but there is one that my brain just can't accept, but it might be right. The original cap is a 10uf 25V NP. That's what I ordered from a short list of available caps. I knew it was smaller, but this is crazy. The original is 15mm x 35mm with 10mm leads. What I got is 4mm x 10mm with 2mm leads. From the schematic (C322), this cap is in the horizontal circuit before the yoke.

I'm attaching the section of the schematic as well as the size comparison pic. Will this little cap actually work, or do I need to get one with higher voltage in order to get something similar is size (12.5mm x 25mm)?

Thanks!

[damen]

Original cap has specific characteristics for that application. Your sub won't hold up.

[TinCanAlley]

Originally Posted by damen

Original cap has specific characteristics for that application. Your sub won't hold up.

This is the closest I can find to the original in size.

https://www.mouser.com/ProductDetail...lX2SHnPQ%3D%3D

[old_tv_nut]

Originally Posted by TinCanAlley

This is the closest I can find to the original in size.

https://www.mouser.com/ProductDetail...lX2SHnPQ%3D%3D

That doesn't look like a non-polarized (NP) cap. The application requires non-polarized.

I can find some on Amazon, but I don't know
1) if the supplier is trustworthy
2) if the original part has some additional unique specification, for example, ripple current

Here are the ones on Amazon, which are advertized for audio crossover circuits, just FYI:
https://www.amazon.com/Cermant-Non-P...39&sr=8-3&th=1

[TinCanAlley]

Originally Posted by old_tv_nut

That doesn't look like a non-polarized (NP) cap. The application requires non-polarized.

I can find some on Amazon, but I don't know
1) if the supplier is trustworthy
2) if the original part has some additional unique specification, for example, ripple current

Here are the ones on Amazon, which are advertized for audio crossover circuits, just FYI:
https://www.amazon.com/Cermant-Non-P...39&sr=8-3&th=1

It is non-polarized, but I no longer need it. I feel like I pay attention, but sometimes my outcomes say otherwise. I've been so focused on finding what blew on the video board, I completely ignored the reversed cap I removed from the power supply. I was cleaning out my old parts bin when I came across the one I reversed and then had to remove. While It looked fine, it was the source of the hiss and smoke. While the top was pretty flat, all the outside ends of the of the score lines had little pinholes in all four corners (video microscope helped greatly). So the pressure didn't bulge the canister or dome the top, it did blow out 4 little holes at the end of each score line.

Noting this, I put the supply back in and reinstalled the video board. It fired up just fine and performed all functions just fine.

[DavGoodlin]

Just a question: Is yoke winding that driven from the flyback, in parallel?

That cap is in series with the yoke, a very low-impedance circuit that may not see higher pulse voltages.
This is similar to a tuned speaker crossover, yoke horizontal coil like a woofer, where you want the energy to go.