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[CLD-D505] No power
https://forum.lddb.com/viewtopic.php?f=53&t=10449		 Page 2 of 2
Author:  drhoeh [ 20 Jul 2022, 04:55 ]
Post subject:  Re: [CLD-D505] No power
I really appreciate all the support as we try to figure this out.

Using the case as a ground I tested for DC voltage at D204 and I got nothing.
I did start to trace voltages down the AC lines, being very careful to not light myself up like a christmas tree.

I did recieve the following voltages, I don't know if they standout. I do know that ohms is more effective but this is best I can do with midnight approaching and work in the morning.

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File comment: Some voltage numbers...does anyting standout?
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Author:  krbahr [ 21 Jul 2022, 01:55 ]
Post subject:  Re: [CLD-D505] No power
If your not getting the DC voltages then the little 1uf cap others have told you to buy is likely bad. If it is bad it does not produce the startup pulse required to get the switching circuit on the primary side of the power supply going. If the cap is good then something else in the switching section on the primary side is bad. Switching power supplies require the startup pulse and then operational pulses to be supplied to enable the DC generation. Your readings look like the switching section in the primary side is not operating. You need to fix that before you look elsewhere.
Author:  drhoeh [ 21 Jul 2022, 03:44 ]
Post subject:  Re: [CLD-D505] No power
I really appreciate your advice, I did test the capicator that I replaced on the DC side. That does not mean that my new capacitor tester is any good. I will replace that capacitor.

If that does not resolve the issue do you have any suggestions on what to do next?
Author:  krbahr [ 21 Jul 2022, 23:50 ]
Post subject:  Re: [CLD-D505] No power
If you replaced the 1uf capacitor with a new one then you have another part in the primary or the optical coupler between the primary and secondary side bad. After the startup pulse the secondary should produce +5VDC which is fed back to the primary thru the optical coupler and then the pulsing circuit decides how much primary pulse to pass to the secondary to keep the voltage at +5VDC. Sounds like this is what is failing. Remember this is a switching power supply and without this feedback pulsing controller working the supply will not produce any DC voltage.
Author:  drhoeh [ 22 Jul 2022, 22:11 ]
Post subject:  Re: [CLD-D505] No power
Would I be better off to search for similar Laserdisc player for parts? If so is there anyway to tell if the power supplies are compatible. I ask because I saw a Japanese CLD-K8v in a Goodwill and I was curious if the power supply could be swapped out. Either way I will keep on trying to figure out this powersupply.

Also I removed the 1uf capacitor out C120 and tested it. I got .91uf, are the tolerances that specific?
Author:  krbahr [ 22 Jul 2022, 22:32 ]
Post subject:  Re: [CLD-D505] No power
CLD-D605, CLD-D606, and CLD-D406 use similar supplies
Author:  drhoeh [ 22 Jul 2022, 22:51 ]
Post subject:  Re: [CLD-D505] No power
Thank you very much.
Author:  drhoeh [ 22 Jul 2022, 23:09 ]
Post subject:  Re: [CLD-D505] No power
I have been removing testing and replacing capacitors when needed. What tolerance do I replace a capacitor? For example if the cap is 1up and I measure .91 should that be replaced?
Author:  krbahr [ 24 Jul 2022, 05:49 ]
Post subject:  Re: [CLD-D505] No power
There is the optical isolator, resistors, transistors, etc used in the pulse control circuit on the primary side, it does not have to be a capacitor.
Author:  drhoeh [ 24 Jul 2022, 22:02 ]
Post subject:  Re: [CLD-D505] No power
I really do greatly appreciate all of advice. So far I have been working my way across the primary side testing everything I can. The image below shows the reading I have so far. I tested for voltage plugged in but not connected to the player. The ohms were taken with no power.

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Author:  krbahr [ 25 Jul 2022, 02:50 ]
Post subject:  Re: [CLD-D505] No power
Doing all this would be good if this was a linear power supply.

This is a switching power supply and you need an oscilloscope to see if the switching control issues any pulses to control the power supply primary sending voltage to the secondary. You need to read up on switching power supply theory or just swapping out parts until it starts working.
Author:  cplusplus [ 25 Jul 2022, 14:52 ]
Post subject:  Re: [CLD-D505] No power
drhoeh wrote:
Also I removed the 1uf capacitor out C120 and tested it. I got .91uf, are the tolerances that specific?

No. Vast majority +-20%

D101 should not be outputting 0VDC.
Author:  drhoeh [ 26 Jul 2022, 04:15 ]
Post subject:  Re: [CLD-D505] No power
It sounds like I have an on going project. I will take a deeper look into D101 and see what I can figure out. If anything with all the help I am getting, I'm learning alot. This is a little out of my field, but it is interesting.
Author:  krbahr [ 28 Jul 2022, 02:20 ]
Post subject:  Re: [CLD-D505] No power
cplusplus wrote:
D101 should not be outputting 0VDC.


cplusplus take a closer look at his readings, in the picture he has 0V on the plus output of D101 and 120V on the minus output of D101. His meter is either connected incorrectly or D101 was flipped when installed. There is also a 120 added reading pointing close to D101 output. The readings need to be updated to VAC or VDC and what ground point used measure the voltages.

I would first replace the opto coupler and see what happens after it is clear what is coming out on the + and - pins of D101.
Author:  drhoeh [ 29 Jul 2022, 11:35 ]
Post subject:  Re: [CLD-D505] No power
Thanks, I am first going to recheck D101 readings and verify that they are correct and go from there.
Author:  drhoeh [ 31 Jul 2022, 05:03 ]
Post subject:  Re: [CLD-D505] No power
If I understand this correctly I should get DC voltage off of the + / - negative terminals on a rectifier. I get 170v DC when testing for DC along the terminals. Am I reading this correctly?
Author:  krbahr [ 01 Aug 2022, 01:21 ]
Post subject:  Re: [CLD-D505] No power
drhoeh wrote:
If I understand this correctly I should get DC voltage off of the + / - negative terminals on a rectifier. I get 170v DC when testing for DC along the terminals. Am I reading this correctly?


For a switching power supply the Diode bridge creates DC voltage from the AC voltage and then the switching control circuit pulses the DC level on/off at the frequency required to maintain the proper output on the secondary. The Optical Coupler sends a signal from the secondary to the Primary to let the control circuit adjust the pulse to maintain proper secondary output. If you don't have an oscilloscope to see if the switching circuit is operating to create the pulses then you'll just have to swap parts and pray you got it.
Author:  drhoeh [ 02 Aug 2022, 02:11 ]
Post subject:  Re: [CLD-D505] No power
The good news is I was able to get an osciliscope from work, the bad news is I now need to figure out how to work it.
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