Brenell Mini 8 repair. Psu d sub cable pinout?

[tedsorvino]

Hi everyone and best wishes for the new year.
I have a couple of questions regarding a pretty old British semi-pro reel 2 reel multitrack recorder (late 70s) the 8 track 1’’ model, Brenell Mini 8. At the moment I’m in the middle of repairing a unit.

I found in the allen & heath (parent company) technical database, an archive folder with some relevant documents and by following them I managed (nearly) to rebuild the long damaged - non existent power supply and oscillator unit. The company themselves couldn’t provide any more assistance since all their other documents are lost.

The problem is that my unit itself is powered by a 15 pin d sub connector coming from the external power supply unit. Some other similar units are powered by 2 different supplies (7+11pin I think???)
Unfortunatelly I find no pin diagram of the 15 multi-way connector and I can’t figure what pin carries what voltage etc. Finding the ground pins it’s quite easy. The ac motor lines seem not unmanageable to find but the 4 dc lines are quite hard.
By studying every page notes, it seems that the pinout diagram is in a schematics page that it’s not contained in that folder, so it’s impossible to make the new pin connections on the connector cable correctly and I can’t risk anything since it’s power related.

Also a photo (or list) of all the resistors and trim pots (values), of that original psu would really help, since there are a couple of resistors and a trim pot missing from the schematics. I find information and parts “here and there” but never had the chance to study the original psu a bit.

The documents that are included in the Allen & heath folder are very helpful but there are certain parts that are missing and some parts are just different. Apparently there was a mk1 and a mk2 models. The unit I’m repairing is a black Mk1.

So I would ask you if any fellow member could possibly help me with relevant info or direct me to somebody who may have such technical information (already contacted mr Jones who has plenty on hus dedicated vintage Brenell consumer reel site - no reply yet).

Thanks in advance

 

[tedsorvino]

New psu built. Machine mostly fixed. It’s nearly ready. 85%. Just a control relay was needing serious cleaning and still it occasionally gives a couple of transport response headaches. But I know where to look at if it eventually becomes annoying.and track problems on the outer edge track. Track 1. Not transport geometry or heads. Problems with the actual track pcb. It will be fixed eventually.
Not a dead end since it’s an absolutely modular machine. Fixed and calibrated. Here it is.

 

[rob aylestone]

That's a nice machine - it was aimed at small studios, so was really professional users, just the smaller studios. Way too expensive for the likes of me and others with 4 tracks! The barrier between 4 and 8 track was massive. Glad you got it sorted. I take it the wiring got sorted somehow.

 

[tedsorvino]

That's a nice machine - it was aimed at small studios, so was really professional users, just the smaller studios. Way too expensive for the likes of me and others with 4 tracks! The barrier between 4 and 8 track was massive. Glad you got it sorted. I take it the wiring got sorted somehow.

Actually it took a lot of research, work, advice from the very few who knew a lot of things about the machine (actually even people who were involved in its building) and I’ve got quite a lot of experience on building audio stuff and own some good tools. I guess I ‘ve learnt quite a lot about the machine so far.
I don’t think the cost of the complete machine repair and psu rebuild for someone not technical enough would be visible.
And as I said there are a couple of things remaining but music making and recording is a priority and it’s a good tool for that purpose.
Yes it can become better, like every other piece of studio equipment, with exotic components, superbly precise extraordinary calibration….but not for me.