I received a non working Daytek DCM-17WT (circa around 2002/2003). I'm not the original owner so I don't know the history. It is a hybrid LCD TV/computer monitor. The TV side has S-video and composite inputs. The "PC" side has a single VGA input.
SETUP
=====
- known working VGA cable, 15 pin male to male
- known working laptop with VGA output
- known working AC power surger protector
- laptop plugged into Daytek PC side with known working VGA connections
- remote control has fresh known working batteries
- known working DVD player and composite cable plugged into TV side
SYMPTOMS
========
- press power button and Daytek LED will turn green, but there is no picture at all. No flash of the screen, nothing. LED stays green.
- pressing the OSD menu on the TV or remote shows nothing
- pressing the source button on the TV or remote control does not display any picture
- I cannot be sure what the "source" is because there is no OSD display or menu
- if I remove the LVDS cable, the screen goes entirely white and stays that way which infers the inverter board and CCFLs are working okay
- there is a slightly high pitched whine or squeal with the LVDS cable is plugged in. If I disconnect the LVDS cable, that sound is gone.
MEASUREMENTS
============
- external power supply DC12V 4.17A shows steady 12.22V DC with DMM
- inverter board gets 12V DC with DMM
- all fuses show 0.03 ohms with DMM
- LVDS (from left to right) DC voltages are
pin 1-4: 4.88V DC
pin 5-8: 0.00V DC
pin 9: 1.34V DC
pin 10: 1.19V DC
pin 11: 1.34V DC
pin 12: 1.19V DC
pin 13: 1.25V DC
pin 14: 1.28V DC
pin 15: 1.24V DC
pin 16: 1.28V DC
pin 17: 1.36V DC
pin 18: 1.17V DC
- I have no ESR meter, but all the caps look visibly okay except one that *might* have been slightly bloated which I changed. All the original caps are real "K" vent Rubycon YK 85C.
- all front panel buttons test okay (no shorts)
NOTES
=====
- the cap I changed out took a lot of heat, scraping, struggles to get out and I think I damaged or removed the solder pads which explains why it looks so ugly. Solder doesn't stick to PCB very well. The front side logic picture shows the "old" cap in. It looks slightly bloated and I replaced it with a United Chemicon.
- I did test the monitor BEFORE I changed the one cap and I got almost the same voltage measurements on the LVDS.
- I have reseated and cleaned all the connections and verified cable integrity with a DMM using the continuity test.
- I think the problem lies somewhere on the logic board, possibly the pixelworks PW166B-10T chip. I suspect that for two reasons.
First,it looks like it is the chip that processes both PC and TV side inputs. Since neither composite or PC work this might be the choke point.
Second, it looks like this is a BGA implementation and there are numerous reported problems with this type of implementation.
- Datasheet for PW166B is at
http://www.eserviceinfo.com/download.php?fileid=24584
NEXT?
=====
Since the PW166B is a BGA, I cannot easily verify it is working properly. I guess I can infer it is working or not by measuring the outputs and comparing it to the datasheet.
So I'm looking for suggestions on how to proceed or test points.
If the suggestion is to recap the logic board, I can, but I need to order some caps that fit. As you can see, some caps lie on their side to fit underneath the aluminum shield. And these are already Rubycon caps, albeit 2002/2003 circa.
SETUP
=====
- known working VGA cable, 15 pin male to male
- known working laptop with VGA output
- known working AC power surger protector
- laptop plugged into Daytek PC side with known working VGA connections
- remote control has fresh known working batteries
- known working DVD player and composite cable plugged into TV side
SYMPTOMS
========
- press power button and Daytek LED will turn green, but there is no picture at all. No flash of the screen, nothing. LED stays green.
- pressing the OSD menu on the TV or remote shows nothing
- pressing the source button on the TV or remote control does not display any picture
- I cannot be sure what the "source" is because there is no OSD display or menu
- if I remove the LVDS cable, the screen goes entirely white and stays that way which infers the inverter board and CCFLs are working okay
- there is a slightly high pitched whine or squeal with the LVDS cable is plugged in. If I disconnect the LVDS cable, that sound is gone.
MEASUREMENTS
============
- external power supply DC12V 4.17A shows steady 12.22V DC with DMM
- inverter board gets 12V DC with DMM
- all fuses show 0.03 ohms with DMM
- LVDS (from left to right) DC voltages are
pin 1-4: 4.88V DC
pin 5-8: 0.00V DC
pin 9: 1.34V DC
pin 10: 1.19V DC
pin 11: 1.34V DC
pin 12: 1.19V DC
pin 13: 1.25V DC
pin 14: 1.28V DC
pin 15: 1.24V DC
pin 16: 1.28V DC
pin 17: 1.36V DC
pin 18: 1.17V DC
- I have no ESR meter, but all the caps look visibly okay except one that *might* have been slightly bloated which I changed. All the original caps are real "K" vent Rubycon YK 85C.
- all front panel buttons test okay (no shorts)
NOTES
=====
- the cap I changed out took a lot of heat, scraping, struggles to get out and I think I damaged or removed the solder pads which explains why it looks so ugly. Solder doesn't stick to PCB very well. The front side logic picture shows the "old" cap in. It looks slightly bloated and I replaced it with a United Chemicon.
- I did test the monitor BEFORE I changed the one cap and I got almost the same voltage measurements on the LVDS.
- I have reseated and cleaned all the connections and verified cable integrity with a DMM using the continuity test.
- I think the problem lies somewhere on the logic board, possibly the pixelworks PW166B-10T chip. I suspect that for two reasons.
First,it looks like it is the chip that processes both PC and TV side inputs. Since neither composite or PC work this might be the choke point.
Second, it looks like this is a BGA implementation and there are numerous reported problems with this type of implementation.
- Datasheet for PW166B is at
http://www.eserviceinfo.com/download.php?fileid=24584
NEXT?
=====
Since the PW166B is a BGA, I cannot easily verify it is working properly. I guess I can infer it is working or not by measuring the outputs and comparing it to the datasheet.
So I'm looking for suggestions on how to proceed or test points.
If the suggestion is to recap the logic board, I can, but I need to order some caps that fit. As you can see, some caps lie on their side to fit underneath the aluminum shield. And these are already Rubycon caps, albeit 2002/2003 circa.
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