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Re: LDR for the SCC

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ldr scc
3K views 10 replies 5 participants last post by  Karl 
#1 ·
Re: LDR for the SCC

Saw this on one of the other Saab forums, so I made a quick note of it:

Photo cell for trip computer- available from Maplins, part no.:N47AY (range 16k-23k Ohms LDR)

Hope this helps.
 
#7 ·
Originally posted by Mark E:
[qb]Hmm, that doesn't match the impedance I measured which was circa 400kOhm in bright direct light to circa 7MOhm in darkness...

I've tried searching but haven't found anything in that range. [/qb][/b]
Mark, was that the resistance of a correctly functioning LDR. I stripped my SCC to look for serial numbers yesterday to no avail.

It seems like this is a common fault with the SCC. I checked the analogue clock on my other 9k, and the LDR was physically different. I may just buy a selection for the SCC from RS and play around. I'll let you all know if I get is sorted out....

Simon
 
#9 ·
Ok, my SCC now works correctly.

I used an LDR N49AY LDR from Maplins it was £0.99 for the LDR and around £2.50 for next day delivery

Its a 10 minute job to remove the SCC and re-solder the LDR in. You can connect it either way round. There are 3 holes in the PCB, so make sure you push the LDR legs through the same 2 holes that are currently used.

The old LDR was open circuit (over 20 MOhms), so the display was maximum dim. It works very well now and reacts even when driving through tunnels.

Hope this helps- it was annoying me for around a year and only cost £3.50 to fix

Simon
 
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