No picture Bush BPDP42HD2

[Giff1711]

Hi
My problem His no picture the tv powers on and will even goto sleep after being left on. But when I test for correct voltage at test points Vs 207. Va 55 I get nothing (Except when I first turn on it measure correct for a second) The only voltage's i'm getting are the D15v on cn804 & the voltages on cn802.
Disconnecting y& z boards does not make a difference. I have tested the diodes and all off the transistors bar one which seems to be a Off-Line SMPS Current Mode Controller with integrated 650V CoolMOS and Startup cell (frequency jitter Mode) in FullPak . I noticed the led on the logic board flashes once every 10s maybe If I can prove for certain its the psu At least I know what to replace if I can't fix it. Any help or guidance on this matter would be very much appreciated.
Thank you
pic enclosed

[selldoor]

Re: No picture Bush BPDP42HD2

any sound?
EDIT
Sorry mostly a brainfart as they say across the pond - was actually thinking of another thread entirely

[selldoor]

Re: No picture Bush BPDP42HD2

Hmm - no replies - did you read this - may help if you have not
https://www.badcaps.net/forum/showthread.php?t=18542&

[tom66]

Re: No picture Bush BPDP42HD2

Voltages correct for 1sec indicate X- or Y-main fault.

[Giff1711]

Re: No picture Bush BPDP42HD2

I still get same readings when x&y boards are unplugged. (The way its designed I can't just plug x bd in to see if I get sound)
If the problem was there wouldn't the voltages go up when unplugged ?
could the logic board affect those voltages vs & va ?
thanks for reply

[Giff1711]

Re: No picture Bush BPDP42HD2

Hmm - no replies - did you read this - may help if you have not
https://www.badcaps.net/forum/showthread.php?t=18542&

Thanks I've already looked at links for common problems
Theirs no sound & blank screen. Apart from that it swiches on & goes to sleep if left on

[tom66]

Re: No picture Bush BPDP42HD2

Unplugged X- and/or Y-main will lead to detection of fault. Check LED on control board. Does it blink approximately once every second, or once every 5 to 7 seconds?

[crt man]

Re: No picture Bush BPDP42HD2

Hi
There are two faults with this set I have repaired six of these now,
I take take it that you have sound but no picture?
if that is the case,

1 Does the relay click once , if so then you have a short on the Y Buffer, if you are in the dark you should see the screen try to start, then go blank.
Replace the Y buffer and all will be well.

2 Does the rely click three times, if so then the Y buffer has shorted, but it has shorted the Two FETS
on the X Main. ( it is the two on the outside of each other on the bank of six RJH30E2 x2 )
These need replacing along with the Y buffer.

Be careful ordering the Y buffer, alot being sold come from cracked screens but some these are faulty,
Of the six I have replaced I have had Ten faulty ones which had to be returned.
If you need any more help let me know.

HTH
Alan.
Hi,
I had not read your thread when I sent reply'
I suspect it is the second option on your set do not worry about sound as I found on the last one I repaired the tuning settings had been lost and there was no stored channels resulting in no sound.

Thanks


I have sent the original poster this reply as a PM was sent to me,and I did not see this thread till afterwards.

Alan

[tom66]

Re: No picture Bush BPDP42HD2

That is good info, but I have not yet heard of Y-buffer faults on these sets? Do the buffer chips burn with this fault?

[crt man]

Re: No picture Bush BPDP42HD2

Tom,

No they do not burn,
All I know is that with every case there is one short on one of the IC's
resulting in no picture, or two or three shorts on one IC, Which short the two Fets on the X Main

Alan.

[tom66]

Re: No picture Bush BPDP42HD2

I have heard that a bad plasma panel can cause that fault, too. Not heard of it on the B450 Samsung though, which use a similar panel. (The B450 panel is made in Hungary whereas the Bush panel is made in a different factory in China.)

I too found a bad buffer board when pulled from a cracked B450, the other boards were OK though including X-main.

[crt man]

Re: No picture Bush BPDP42HD2

Hi
Of the six I have repaired there is a split down the middle.

Three were just Y buffer shorts and the other three were Y buffer
shorts along with X main faults.

Alan.

[flocko]

Re: No picture Bush BPDP42HD2

i have also had to replace all three boards on this model YSus /Y buffer and XSus shorts to all, buffers ICs dont show damage only when you run a meter over them

[crt man]

Re: No picture Bush BPDP42HD2

I have never replaced the Y /Sus even though I was told to,
no fault found , just the Y buffer and FET's on the X/Sus
I now have Three spare as a result.

Alan.

[satinser]

Re: No picture Bush BPDP42HD2

I also have a problem with a BPD42HD2. Found a short on y buffer also found 2x RJE30E2 shorted on xsus board as crt man has previously reported earlier in this thread. Ysus board appears to be ok. Aquired replacment y buffer which has tested ok with no shorts and replaced the 2 RJH30E2 on xsus board Thought it best to try initially without y buffer fitted. Xsus board worked for about 10 seconds then clicked 3 times and the 2 RJH30E2 have blown again.
Anybody have any ideas why they should have blown again? Any chance that it was because of the absence of the y buffer?

[tom66]

Re: No picture Bush BPDP42HD2

I would advise replacing the driver ICs whenever replacing the IGBTs as the IGBT failure can damage the driver ICs.

The driver ICs are right near the IGBTs, usually surface mount 8 pin devices.

[satinser]

Re: No picture Bush BPDP42HD2

Many thanks for your reply. I will obtain a replacement board in that case as not to expensive rather thn trying to source those ics.

[ron77]

Re: No picture Bush BPDP42HD2

In process of repairing Bush BPDP42HD2. This is first time have come across this model. Found Q4001 and Q4007 s/c, also s/c in buffers. The owner of tv did say the set only broke down when he fitted it on wall. After what Tom said in post 11, I could be gambling more than usual on this one. Now, to question I want to ask, it concerns price mostly. Tvspareparts had buffer for just under £31, inc p&p. That is about £20 cheaper than any other price I saw, but sold out. Had stocks for Hitachi Ps42c450, so bought one thinking they are identical, am I right. The Hitachi panel same price as Bush, on iOffer website

[ron77]

Re: No picture Bush BPDP42HD2

Made mistake, mean Samsung, not Hitachi.

[ron77]

Re: No picture Bush BPDP42HD2

Had same problem as giff1711, also didn't know where to start. Had set that had vs and va at switch on, but disappeared very quickly. Found if removed plug at cn804, that disconnects vs and va from psu. Also disconnect flexible connector from control to y board at cn5003 psu stays on. Removed q4001 and q4007 from x board, both s/c and could replace cn804 plug, meaning all plugs connected, and psu vs and va voltages, stay on, that is with my boards. Make sure no s/c on x and y board. Before I go on, green led. on control board will be flashing about once a second. If control board reconnected, led flashes about every 5 seconds, and vs and va will drop. From here if you obtain a good x board, y board, and buffer, tv should work if plasma panel is ok. Fitted replacement x, y, and buffer, these panels were ok by the way, didn't know it at time, but tv did not work. Heat sinks stone cold on x and y boards. So disconnected plasma panel, 8 connections and switched on. For first time heat sinks on x and y board began to warm up. Tv running normally. Reconnected plasma panel and to my surprise set did not shut down, and actually saw small bits of brightness on screen. Sometimes brightness, sometimes blank screen at switch on. Take good panels out and it is ready for tip. Plasma panel u/s.