ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
greetings all 🤗
can someone supply a matched pair of these LDRs for my Beogram4000 ?
the part according to the SM is a ORP61 light-dependant resistor from the servo regulating assembly.
If you can offer a pair please reply and/or PM me.
many thanks
ALF
Are yours bad?And why a matched pair?
Martin
Through the top opening slots they show about 160ohm to 105ohm which is a huge difference !
shouldn’t both be around even ?
no light resistance shows ‘OL’ for both
The LDRs will be even - within some tolerance (25-50% or so) - if the light that falls on them is exactly even and from the exact same angle.Noone can guarantee that under normal working conditions.The lamps filament may point slightly more towards one side, the distance from lamp the LDRs will not be 100% the same.And with the covers off, you will have ambient light influence.
It makes no sense to find matched LDR pairs.The motor doesn't run equally fast in both directions - and it doesn't have to.The H-bridge not built with matched transistor pairs andyou will be adjusting the tracking sensitivity anyways...- Besides, how many times will it ever need to track outwards?
That seems to be the main problem: tracking outwards !!!
that is the only way I am getting from the servo at the moment if anything.
it simply won’t track /engage inwards.
both ORPs are still in their black plastic fitting and as said, put on a flat surface with only light getting in from the top
one LDR shows about 160ohm while the other shows about 105ohm.
even with a 25-50% tolerance I can not turn them in their fitting to make them more even.....!
as said in my last post on the Beogram forum:
adjusting the height of the diagphram and /or light intensity from OL1 the servo simply won’t engage inwards.
Check the signals in the H-bridge instead.It's far more likely to be where the problem is.
Nevertheless,
i sourced some NOS ORP61 from germany....just in case
it did not break the bank 😁🤙