Enterprise Forever

:UK => Wanted => Topic started by: keyboardjunkie on 2019.July.13. 00:02:35

Title: UM1233 RF Modulator
Post by: keyboardjunkie on 2019.July.13. 00:02:35

Hey All,

Has anyone got a spare, working UM 1233 RF modulator they are willing to part with?

I'm currently ressurecting a car boot sale find - an old EP128 (board only) that had been _very_ abused.  I've got it working but the RF ouput is making a buzzing noise on the picture and all the colours appear wrong (background on the flashing EP logo at first boot is a fuzzy blue colour) and all the text on the screen appears to be 'bleeding' a fair bit like it's off channel.  Tried everything to get it looking better and now I wonder if the RF modulator is broken..

EP appears to work fine apart from that - I'll attach a picture for you experts to take a look at!

Also, Had to replace a missing LM1889 IC - I think there should have been a resistor across 2 pins of the IC if I recall - anyone got any info about it?  I'll post a pic of the board too..

Thanks for any help you guys can give me!

Mark.

Title: Re: UM1233 RF Modulator
Post by: Zozosoft on 2019.July.13. 07:23:30

There is brand new on Ebay. (https://www.ebay.co.uk/itm/Astec-UM1233-UHF-modulator-Channel-36-um1233-E36/401773394660?epid=644349398&hash=item5d8b8f7ae4:g:~MEAAOSwh6xTtqov)

But why using RF? RGB SCART is the best :-)

Have you tried to play with the variable resistor near the left side of the modulator?

I see EPower installed, nice!

Title: Re: UM1233 RF Modulator
Post by: keyboardjunkie on 2019.July.13. 22:56:32

Hi Zozo!

Hope you are well friend!

I wanted to get the EP as original as I possibly could - and a new modulator seemed like a must have :-)

I have tried the pot next to the modulator to no avail - I guess my next job will be to scope the video signal into the modulator to see if it looks good - but I think that the modulator is bad (the rust might be the cause!)

I may buy that one on ebay and replace it anhyhow.

I need also to get a 128k upgrade for it - do you have any for sale?

I will also need to look for a case to put it in, but I guess that will be very hard to find..

The power side of the EP was completely broken - it was much easier (and a better choice) to replace it with an EPower module - no need for a heatsink (which I don't have either and may need to try and make something)

If you have any parts - or know anyone with parts - a case, heatsink etc. I would love to find these.

Thanks Zozo!

Mark.

Title: Re: UM1233 RF Modulator
Post by: Judge on 2019.July.14. 12:49:01

Hello
I'm Judge from the ENTERPRISE FOREVER forum.
I have such a part. My daughter goes back to Newcastle on Monday. Where do you live and how can you get it?
Sorry, I could only write with Google Translate ...

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