Sign in   |  Join   |  Help
Click here to change your Beoworld Account Details

ORP61 wanted for Beogram 4000

rated by 0 users
This post has 6 Replies | 1 Follower

ALF
Top 100 Contributor
AUS
Posts 772
OFFLINE
Silver Member
ALF Posted: Tue, Nov 13 2018 10:31 AM

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

 

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 10,520
OFFLINE
Founder
Moderator
Dillen replied on Tue, Nov 13 2018 2:30 PM

Are yours bad?
And why a matched pair?

Martin

ALF
Top 100 Contributor
AUS
Posts 772
OFFLINE
Silver Member
ALF replied on Wed, Nov 14 2018 12:44 AM

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

ALF

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 10,520
OFFLINE
Founder
Moderator
Dillen replied on Wed, Nov 14 2018 7:37 AM

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 and
you will be adjusting the tracking sensitivity anyways...

- Besides, how many times will it ever need to track outwards?

Martin

ALF
Top 100 Contributor
AUS
Posts 772
OFFLINE
Silver Member
ALF replied on Wed, Nov 14 2018 8:59 AM

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.

 

ALF

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 10,520
OFFLINE
Founder
Moderator
Dillen replied on Wed, Nov 14 2018 9:58 AM

Check the signals in the H-bridge instead.
It's far more likely to be where the problem is.

Martin

ALF
Top 100 Contributor
AUS
Posts 772
OFFLINE
Silver Member
ALF replied on Thu, Dec 6 2018 12:33 PM

Nevertheless,

i sourced some NOS  ORP61 from germany....just in case

it did not break the bank 😁🤙

ALF

Page 1 of 1 (7 items) | RSS
Beoworld Security Certificate

SSL