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Old 03-20-2020, 08:56 AM   #21
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

D7910 (cathode) = 14.44VDC
D7904 (cathode) = 14.96 VDC
D7919 (cathode) (should be 18v) = 12.18VDC
J7801 (should be 15v) = Cannot locate this Jumper... do you have another component that is on this node?
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Old 03-20-2020, 10:02 AM   #22
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

I made a typo, That should have been, J7081, it is Q7902 emitter. it is the VCC-on voltage that turns on the relay plus various other transistors. It must be supplying some voltage because the relay is switching.
D7910 (cathode) = 14.44VDC
D7904 (cathode) = 14.96 VDC
Thes two votages seem low, they should be at least 20v, I would replace C7918 and C7915 and see if that makes a difference to the voltages.

Last edited by R_J; 03-20-2020 at 10:27 AM..
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Old 03-20-2020, 10:25 AM   #23
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

J7081 = 13.56 vdc
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Old 03-20-2020, 11:37 AM   #24
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Quote:
Originally Posted by R_J View Post
I made a typo, That should have been, J7081, it is Q7902 emitter. it is the VCC-on voltage that turns on the relay plus various other transistors. It must be supplying some voltage because the relay is switching.
D7910 (cathode) = 14.44VDC
D7904 (cathode) = 14.96 VDC
Thes two voltages seem low, they should be at least 20v, I would replace C7918 and C7915 and see if that makes a difference to the voltages.
I just replaced both caps and the voltages stayed the same.
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Old 03-22-2020, 02:15 PM   #25
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

It's a shame to throw in the towel on this TV as I'm pretty sure the issue with it is something minor, but without a schematic, it may take more time than it is worth to figure it out. I guess I could part-out the remaining good parts on eBay.
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Old 03-22-2020, 06:06 PM   #26
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

If you have around 12 volts on IC7801 pin 8, that should be high enough for the pFC circuit to operate. But if the ic is damaged and not outputing a drive signal to the two fets, you won't get the boosted voltage. You might also want to check the voltage on pin #3 or mabe easier/safer, check the voltage on J7022, and then on both sides of R7812, this voltage should be around 2~4 voltsdc

If you don't have the equipment (scope etc.) to check the circuit, the only choice you have is to replace the ic. and see if it makes a difference.

Last edited by R_J; 03-22-2020 at 06:14 PM..
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Old 03-22-2020, 08:31 PM   #27
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

I have a scope. Will check for gate drive signals. Do the Overvoltage protection circuits shut down the PFC circuits? Just wondering if it would make sense to disable them to see if maybe a problem there could be in play.

Last edited by bznhvx; 03-22-2020 at 08:34 PM.. Reason: Additions
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Old 03-22-2020, 08:34 PM   #28
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Do you have an ISOLATION TRANSFORMER? you will need one if you are working in the primary circuit.
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Old 03-23-2020, 07:02 AM   #29
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Quote:
Originally Posted by R_J View Post
Do you have an ISOLATION TRANSFORMER? you will need one if you are working in the primary circuit.
Yes, my scope is connected through an isolation transformer. I also have a high voltage probe if needed.

Last edited by bznhvx; 03-23-2020 at 07:04 AM.. Reason: Additions
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Old 03-23-2020, 09:01 AM   #30
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

IC7801
pin 8 = 13.5vdc
pin 3 = 0.84vdc

J7022 = 4.11vdc
R7812 = 0.83vdc and 4.11vdc

J7022 has a clean looking sinusoidal signal.
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Old 03-23-2020, 09:47 AM   #31
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Did you check if you have gate drive output from the ic?

Last edited by R_J; 03-23-2020 at 09:52 AM..
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Old 03-23-2020, 01:58 PM   #32
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

There are gate drive pulses coming from pin 7 to the pre-driver transistors. This is a very low duty cycle. The pre-drive transistors all pass the static PN junction tests. The output feedback is only at 1V, so the duty cycle should be higher to bring the voltage up.

Last edited by bznhvx; 03-23-2020 at 02:07 PM..
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Old 03-23-2020, 02:24 PM   #33
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

This ic should be operating at around 70khz. I suspect it is bad.
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Old 03-25-2020, 05:49 PM   #34
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

I have checked all the components around the L6562D and don't see any reason for it not to be working, so I am going to order a replacement. The shipping charges are crazy for such a cheap small part, so I want to order a few other spare parts just in case I need them to finish this job. What would you suggest?
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Old 03-25-2020, 08:43 PM   #35
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Where are you ordering it from?
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Old 03-25-2020, 08:48 PM   #36
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Digikey - they ship USPS so usually lowest cost shipping
Thought I would go ahead and get the parts for the standby 5v since those seem to fail from what I hear. TNY264, some PC123 equivalents, a few of the pre-driver transistors PBSS5140T, and a few diodes since I don't have any surface mount parts in my repair stock.

Last edited by bznhvx; 03-25-2020 at 08:49 PM.. Reason: .
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Old 03-25-2020, 08:53 PM   #37
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

I get parts shipped from digikey for $8.00, and they ususally arrive next day.
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Old 03-25-2020, 09:02 PM   #38
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Anything else that I may need that you can think of?
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Old 03-25-2020, 09:05 PM   #39
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Code:
Index	Quantity	Part Number	Manufacturer Part Number	Description	Customer Reference	Available
1	2	497-8928-1-ND	L6562ATDTR	IC PFC CTRLR TRANSITION 8SO		2
2	10	516-1585-5-ND	HCPL-817-000E	OPTOISOLATOR 5KV TRANSISTOR 4DIP		
3	10	493-5378-1-ND	UPS2A010MDD1TD	CAP ALUM 1UF 20% 100V RADIAL		
4	2	596-1255-5-ND	TNY264PG	IC OFFLINE SWIT OTP OCP HV 8DIP		2
5	5	1727-3906-1-ND	PBSS5140T,215	TRANS PNP 40V 1A SOT23		5
6	10	1727-6174-1-ND	BAS316,135	DIODE GEN PURP 100V 250MA SOD323		
7	10	TZMB20-GS08GICT-ND	TZMB20-GS08	DIODE ZENER 20V 500MW SOD80		
8	2	P6KE120ACT-ND	P6KE120A	TVS DIODE 102V 165V DO204AC		2
9	10	BC3678CT-ND	MBB02070C2208FCT00	RES 2.2 OHM 0.6W 1% AXIAL

Last edited by Per Hansson; 03-29-2020 at 08:09 AM.. Reason: Added CODE tags for readability
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Old 03-26-2020, 07:39 PM   #40
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Default Re: Delta DPS-286AP (RDENCA336WJQZ) Troubleshooting

Quote:
Originally Posted by R_J View Post
I get parts shipped from digikey for $8.00, and they ususally arrive next day.
I guess they like you better than me! It takes 3 or 4 days to get here if I am ordering @ Digi-Key . I guess I am living in the sticks!
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