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Avondale Qudos Amp module installation - A few quick questions

S

Simon s

pfm Member
Hi All,

I am new to the DIY side of things (not that this really constitutes that!) I am about to install the NC220 Qudos boards into my Avondale 130Z amps but i have a few queries.

Firstly, when i am desoldering from the signal connection on the NCC200 boards, do i need to remove all solder from the cable and spades on the board ? And when i solder the cable onto the new boards, do i simply tin them first, then solder to the new spade ?

Secondly, when setting the amp bias, i am aware that the NCC220's need 120mA, but do the new boards come with this set already or should i double check anyway ?
On this point, i have a fairly new UNI-T 139C meter and apart from using it for basic 12v battery checks, i have no way of knowing how accurate it is for the mA bias and offset DC. As a guide, i checked the existing bias on the NCC200 boards and they are coming out around 23.8mA, does that sound about right ?

Thirdly, how much thermal paste should i use for the new heatsinks on the Qudos modules ?

I can't wait to get these boards installed but wanted to double check these points first.

Apologies for the daft basic questions but its better to be safe than sorry i figured.

Thanks all

Simon
 
Les is always happy to help and this should be your first port of call.

He would be very unhappy if you didn't succeed with the project for lack of asking advice.

Tel 01246 200096 - Office hours.
 
No...you don't need to remove the solder from the cables you are changing over
Just heat the tag with a hot iron and the wires will come away easily
When re-attaching tin the spade lightly , then solder the cable to it with a "wet" iron

The new boards should come pre set to the ballpark bias
But always worth checking them before going any further
Also check the DC offset (at the speaker terminals)

Les W will be happy to help as others have said...he likes a chat!!
 
Simon
1, Just clean off the excess with a hot clean Iron, re tin both surfaces then add fresh solder when you bring them together
2, as above you will need to check and adjust the the Bias as necessary, be very patient when you first switch on the Bias will not be the correct value but will increase slowly as the temp stabilises this can take up to 30 mins preferably with the lid on or as best you can to cover the top, when it stabilises adjust to the correct value then wait again for it to stabilis, spend some time on this as it is important.
3, The 2 surfaces should be smooth and clean with no raised edges around the bolt holes and no gaps when you trial fit them, dress and raised edges. Heat sink compound should be a very thin layer, put some on the surface and scrape across with a flat plastic scraper so there is only a thin layer, bring the surfaces together and bolt them up tight.
These are not trivial questions and you are right to ask as getting these point's wrong and you could damage your new amps

Alan
 
As I understand, the 130 amps were made with push-on wiring connectors so
fitting NCC220 modules makes for a few minutes job
 
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