Information about the ASTEC UM1286 Modulator

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Alastair
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Joined: Fri Jul 18, 2008 11:33 pm

Information about the ASTEC UM1286 Modulator

Post by Alastair » Tue Jul 04, 2017 11:20 pm

I've been trying to find out information about the UM1286 modulator, specifically what each screw adjusts. Today I have finally found that information hidden inside the service manual for the Memotech MTX 500/512, no wonder it took me so long to find!

The manual can be found at http://www.primrosebank.net/computers/m ... anuals.htm - be sure to download 'MTX 500/512 Service Manual and Technical Information (5MB)' and not the larger size download. The relevant details, including how best to test and set the modulator, can be found on pages 42 and 43.

Does anyone know what 'cable compensators' do?

sixxie
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Re: Information about the ASTEC UM1286 Modulator

Post by sixxie » Wed Jul 05, 2017 10:11 am

Alastair wrote:Does anyone know what 'cable compensators' do?
I think they might compensate for the ca... No, I have no idea :)

Maybe something to do with matching impedance of the co-ax?

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robcfg
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Re: Information about the ASTEC UM1286 Modulator

Post by robcfg » Wed Jul 05, 2017 10:31 am

The funniest thing is I did that pdf version of the MTX 500/512 Service Manual and Technical Information!

I got the manual from a friend and reconstructed as close as possible to the original, including damaged illustrations.

I never thought it would be useful here years later... :mrgreen:

Alastair
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Re: Information about the ASTEC UM1286 Modulator

Post by Alastair » Wed Jul 05, 2017 8:10 pm

robcfg wrote:The funniest thing is I did that pdf version of the MTX 500/512 Service Manual and Technical Information!
Wow, it's a small world. Either that or you Rob are a colossus in the world of retro computing.

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robcfg
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Re: Information about the ASTEC UM1286 Modulator

Post by robcfg » Wed Jul 05, 2017 10:55 pm

Thanks for the compliment!

It is indeed a small world. It's true that I've done a lot of preservation stuff too but nowhere near some people I know.

Always glad to help! :mrgreen:

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