BBC sound to CUB DIN

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blackwitch
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BBC sound to CUB DIN

Post by blackwitch » Thu Jan 16, 2020 1:56 pm

Hi there.

I have a CUBb monitor with the sound capability. So it has a DIN socket for the input.

Here is a pic which is identical to mine.
Image

I'm wondering if anyone could tell me how to wire my Beeb up to have an RCA or jack socket hidden discreetly without damaging the case too much?

I'd also want a cable making to connect from the beeb to the monitor.

Could anyone help me?

Thanks

cmorley
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Re: BBC sound to CUB DIN

Post by cmorley » Thu Jan 16, 2020 2:37 pm

I copied what tricky did - loop the speaker through a jack plug at the back (3.5mm mono in my case). I mounted the 3.5mm socket between the 'reset' hole and the ECONET hole.

Jack in sound -> TV
Jack unplugged sound -> speaker

I added a 3.5mm mono plug to my SCART lead but a separate lead to a DIN plug would be just as simple.

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NealC
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Re: BBC sound to CUB DIN

Post by NealC » Mon Jan 20, 2020 3:59 pm

Hi blackwitch,
I'm wondering if anyone could tell me how to wire my Beeb up to have an RCA or jack socket hidden discreetly without damaging the case too much?
Some (Many? Most?) Beebs have an unused hole in the rear of the case (see attached picture). Its normally covered with the black vinyl, but its easy enough to cut with a sharp knife and push into the hole (as mine has been - I use it for a volume control). The hole is a little large though, so you may have to drill out some large washers (or plastic plate etc), to the size of the connector you want to use. If you don't have or cant use this, perhaps something similar could be done for the Econet port (assuming you don't have this fitted). Otherwise, drilling another hole in the case is an option (place some masking tape on the black vinyl side to try to prevent splitting, start with a small drill and work up to the size you require). Finally, you could just run it out the vent on the back, but I wouldn't advise this.

The BBC's speaker output is on PL15 - a small 2 pin connector just behind the floppy port along the front left of the motherboard. Assuming you dont wont to keep the internal speaker connected, you can easily find some headers that you could solder on to a lead and push on to this (you could even solder directly to it if you really wanted too...)

This is a speaker level output though, which will probably be too much for the monitors input. If you look slightly up and left of PL15, you should find VR1 - this is the volume control, if fitted (if not, I believe it takes a 10K potentiometer). With the speaker fitted, turn this all the way down and, once the speaker is removed and the sound connected to the monitor, slowly turn it up again to a suitable level.
I'd also want a cable making to connect from the beeb to the monitor.
That looks like a 180 degree 5 pin DIN connector - these tend to have somewhat 'standard' wiring (see https://pinouts.ru/Audio-Video-Hardware ... nout.shtml), but you would need to be sure of how the one on the back of the monitor is wired up - unfortunately, a cursory google search didn't turn anything up for me. It's possible the monitor uses different pins to carry the sound signal, and 'jamming wires in random holes until you hear something' is _not_ the recommended method!

If the wiring is standard, you may be able to find a 5 pin DIN to RCA/headphone jack cable ready made, however I think someone is going to have to solder the back of the RCA /headphone jack in the Beeb at the very least (and possibly the potentiometer on the motherboard) - perhaps you know a friendly electrician (a rare beast :wink: ) or hobbyist who could do it for you if you are not comfortable - heck, if you can confirm the wiring and pay parts and postage, I'd probably be prepared to make the lead up for you.

Ultimately, this all depends on how the monitor is wired up - perhaps a search on the model number will turn up a wiring ("pin out") diagram we can use?

HTH,
N
Attachments
BeebSpareHoleMarked.jpg

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