Perma 12

[Guest joewhite903]

Looking for some help, ive just gotten my hands on a perma 12 dimer pack, im looking for as much information about the unit as I can, ive been on the strand archive page but I would like more,. The amazing peice off technoligy has come out off the night club I work in, I know the main tx is dead, but thats not a problem, I Belive some of the Thristers are gone cause when the unit was being used they were giving an output with no control. Hope somebody out there has info on the unit

 

Thanks Joe

[Just Some Bloke]

I Belive some of the Thristers are gone cause when the unit was being used they were giving an output with no control.

 

You'll probably find it's just a triac that's gone rather than a thyristor as the symptom you are describing would fit that diagnosis. Luckily triacs are quite cheap to buy and quite easy to replace. The only problem I can forsee is that they probably don't make them any more! You could try R.B.Lighting who are quite good at finding parts for older kit.

[Guest joewhite903]

I Belive some of the Thristers are gone cause when the unit was being used they were giving an output with no control.

 

You'll probably find it's just a triac that's gone rather than a thyristor as the symptom you are describing would fit that diagnosis. Luckily triacs are quite cheap to buy and quite easy to replace. The only problem I can forsee is that they probably don't make them any more! You could try R.B.Lighting who are quite good at finding parts for older kit.

 

 

Im guessing u have no idea what the strand perma 12 is then , by the fact that u think it has any triacs inside. Each channel has 2 thyristors, Im a lighting Technition, Im just trying to get more info on the whole unit not how to repair it.

 

 

 

(Didnt mean to sound snappy)

[Dmills]

Im guessing u have no idea what the strand perma 12 is then , by the fact that u think it has any triacs inside. Each channel has 2 thyristors, Im a lighting Technition, Im just trying to get more info on the whole unit not how to repair it.

 

Gads man, get a spell checker....

 

Dead simple analogue racks with a back to back thyristor pair for the output device (the triacs of the time having a reliability issue in this application), as I recall there was a problem with the RFI filter capacitors tending to catch fire, easily rectified by replacing them. Control was normally 0 - minus 10V, and there is normally a control power supply installed in the cable termination bay which puts out around -15V for the mini 2 desks there were used with. They were basically the install version of the mini 2.

 

Given these are 30+ year old racks, I would start by replacing all the electrolytic caps as well as the aforementioned mains filter components (Actually, I probably wouldn't bother, life is too short).

 

Regards, Dan

[paulears]

Moderation:

Joe - I've looked at your original post - you did say it was dead, so it's not surprising that people believed you wanted to repair it, not just 'know about it'.

You said "you thought some of the thristers(sic) had gone" because it was on, but not able to be controlled - thyrsitors usually fail off, and triacs on, so an assumption over which is which is quite understandable. There really is no need to be quite so snappy, bearing in mind you are a new member and the person you sniped at is quite the opposite.

 

As has been said over the past few days - if you want an accurate answer, ask a decent question. You say you have seen the info on the strand archive site, but want more? Like what? The spec on the archive which with due credit to Jon is copied below says:

These wall mounted racks are an extension to the Mini-2+ range of packaged controls and provide a hard-wired, permanently installed alternative to portable 6-dimmer packs but are fully compatible. Perma 12 racks are so compact that two can be mounted one above the other with all external wiring entering either at the top or bottom of the pair.

 

Each Perma 12 rack is a complete distribution system for a single, or a three phase and neutral supply including 440V rated close-excess current protection for the 12 dimmer modules each of which is rated for 2000W maximum of 220/240v tungsten lamp load. Each dimmer module is totally self-contained and complete with its own temperature-stable trigger card, pair of tungsten surge rated Thyristors and substantial inductive filter in addition to RFI suppression.

 

Unlike a 6-dimmer pack (with socket outlets) the various lighting loads controlled by a Perma 12 rack can be spread over a 3 phase supply because the external hard-wiring to conveniently grouped socket outlets can ensure the 2 metre phase separation required by U.K. and some other, regulations. Load wiring in flexible cable can be reduced to the minimum.

 

To interconnect with the 2m long flexible cables of a Mini-2+ 2-preset desk eack Perma 12 rack requires a twin 8-pin control socket box to terminate the extra-low voltage control wiring.

If you don't want to fix them, then what info is it that is not in the paragraph above?

 

As far as I remember, the things used the same pcb and heatsink assembly, with a 10A HRC type fuse as protection. Remember, here on the Blue Room SPAG rules!

 

EDIT

 

just noticed this extra link with more info

more strand archive material on mini2 and permus

[Guest joewhite903]

Gads man, get a spell checker....

Thanks for that dan , Sorry bout my spelling though , the spell checker dosent work on this site anymore.Ta joe

 

Joe - I've looked at your original post - you did say it was dead, so it's not surprising that people believed you wanted to repair it, not just 'know about it'.You said "you thought some of the thristers(sic) had gone" because it was on, but not able to be controlled - thyrsitors usually fail off, and triacs on, so an assumption over which is which is quite understandable. There really is no need to be quite so snappy, bearing in mind you are a new member and the person you sniped at is quite the opposite.

Hi paul sorry for ur misunderstanding , In my post I mentiond that the main Tx was dead meaning the (Transformer) for the -15v , Thanks

[Wuddy]

Hi paul sorry for ur misunderstanding , In my post I mentiond that the main Tx was dead meaning the (Transformer) for the -15v , Thanks

 

I'm glad you've cleared that up, in my venacular Tx is an abrieviation for Transmit(er) or possibly Send.

 

And Rx is Receive(er)

[Just Some Bloke]

Im guessing u have no idea what the strand perma 12 is then , by the fact that u think it has any triacs inside. Each channel has 2 thyristors, Im a lighting Technition, Im just trying to get more info on the whole unit not how to repair it.

 

Apologies for not knowing about the lack of triacs in a Perma 12, but, as Paul mentions above, triacs tend to fail on and thyristors off so it was an easy mistake to make.

 

Just out of interest, what are you intending to do with your dimmers if you don't want to repair them?

[Guest joewhite903]

Hi there I love repairing anything to do with lighting (except Abstract VR8's NAsty Things) My idea is to restore it to new and iether sell it on or built a DMX to anologue board for it an put it in a touring case for myself, It is a very lovley peice off kit doesnt weigh that much iether which is good. you dont happen to know what the colour is supposed to be? Its green and black at the moment which I dont know if its due to discolouration or been painted over at some point , Thanks Joe