Mixing CB's with tubes

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Edgecrusher
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Mixing CB's with tubes

Post by Edgecrusher »

Curious if CB's from larger CRT sets can be used with smaller tubes?

The reason I ask is I sit here with two 19/20" tubes I want to use but the boards are both trashed and I got larger boards coming out of my ears!
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Edgecrusher
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Re: Mixing CB's with tubes

Post by Edgecrusher »

I wonder if the power supply is the limiting factor? But then if I'm using one from a 36" set it should be more than enough for a 20". I can't think of a reason the size of the tube would matter.
KPackratt2k
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Re: Mixing CB's with tubes

Post by KPackratt2k »

REMOVED: Completely false information.
Last edited by KPackratt2k on Tue Feb 07, 2023 9:51 pm, edited 1 time in total.
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Josh128
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Re: Mixing CB's with tubes

Post by Josh128 »

lol you guys better do some serious studying up on CRTs before you fucking kill yourselves. Not trying to be dramatic or rude but its painfully obvious you know very little about CRT operation going by your comments.

The flyback and HOT must definitely be compatible with your tube, yoke/deflection coil, & neckboard or something will go smoky quick, fast, and in a hurry. You 100% cant just put a mainboard made for a 36" tube on a 20" tube and expect something not to blow. A 36" tube requires over 35KV for the cathode ray while a 20" needs around 20KV. Flyback voltages and pinouts vary HUGELY because of this. HOT's will go byebye quickly if the inductance of the deflection coil they are plugged into is not what they are designed for. Ive been trying to find a flyback compatible with the Hitachi 27MM20B dual-scans and have had absolutely no luck. I have a working mainboard with no flyback and its useless.
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Re: Mixing CB's with tubes

Post by KPackratt2k »

Right, I almost forgot about that. Definitely important things to keep in mind. If you're lucky enough to have a chassis that has also been used in a smaller set, albeit with some important component differences, having service manuals for both the set the chassis originated from and the smaller version can help you identify what you need to replace, but it's not going to be easy to find replacement parts for really old hardware that's no longer in production.

Here's a thread where someone managed to make a 27FV310 out of a 27FV300 and a 36FV310, this should give you an example on how this requires modification to the point where it's not 100% plug-and-play, but it likely will be more complicated than this depending on what you're dealing with:

viewtopic.php?f=6&t=70131
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Edgecrusher
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Re: Mixing CB's with tubes

Post by Edgecrusher »

Its ok Josh, that's exactly why i asked in the first place. I've only been experimenting with crts for about a year and I'm starting to expand my understanding past just rgb mods.

I have a great resource to pickup free sets, they just aren't usually anything i can use so i started thinking about how a lot of sets share chassis but I knew there had to be differences besides just the extra bells a whistles.
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buttersoft
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Re: Mixing CB's with tubes

Post by buttersoft »

If you're talking tube swaps you need the pinout/socket to line up and the yoke readings to match - or nearly so. Then you can give it a go with reasonable confidence you won't see magic smoke.
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Edgecrusher
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Re: Mixing CB's with tubes

Post by Edgecrusher »

Im not familiar with what you mean by yoke readings.
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Josh128
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Re: Mixing CB's with tubes

Post by Josh128 »

Inductance values of the deflection coils.
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