CurtPalme.com Home Theater Forum

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Hi, I've been searching this forum for quite a while but didn't find something about a specific issue.

I've recently acquired a Sony VPH D50QM (to replace my current Sony VPH 1041QM) with 1777 hours on the tubes. Inside is (very) clean, no dust or cigarette smoke.

However, the red tube won't show a picture, but it does show the on screen menu. So the tube itself seems to be ok.

I've tried a CBVS signal (composite) and RGBHV. Both the same issue.

I've also modified the IFB-40 board; soldered a VGA cable to it (RBGHV). It works (can select switcher as input) and it shows a picture, but again only Green and Blue.

Also tried to swap the small DF-V DF-H boards and the small boards on the input-A board (CN101?)

Any thoughts on this would be highly appreciated.

Greeting from the netherlands!

Boet · Joined: 10 Jan 2012 Posts: 30 Location: Netherlands

I saw that one passing by on MP, had to resist the urge to buy it. Wink

Not familiar with this machine, but...

Since both CVBS and RGBHV show the problem, I'd rule those input boards out ('frontside').
The red tube still displays the on screen menu, I'd rule the output sections out as well ('backside').
Sounds like there's a problem somewhere between the demodulated CVBS / RGBHV and the output section.

Do you have the service manual and an oscilloscope?
Feed the projector a video signal, trace the red and green/blue video lines. See where you lose the red signal (or where it starts to look odd).

**Curt Palme** · Posted: Fri May 01, 2020 2:09 pm Post subject:

The problem will be in the RGB/CPU input board. Without PC board extenders, that's going to be impossible to troubleshoot, since everything is on that board, and buried in the set.

I have one CPU board left at $150 USd incl air shipping to you if you're interested.

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Hi Curt, yes interested. Could you send me a photo of the board? I'm curious how hard it would be to swap. Or is it the default "input A" board?

Thanks for the responses!

**Curt Palme** · Posted: Mon May 04, 2020 5:41 pm Post subject:

IT's the default A board. 2 screws, one on either side, and the whole thing slides out. Email me at curt@curtpalme.com

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Hi Boet,

"Do you have the service manual and an oscilloscope?
Feed the projector a video signal, trace the red and green/blue video lines. See where you lose the red signal (or where it starts to look odd). "

Service manual is on this site I believe, but an oscilloscope? Nope, any idea where I can get some help with this in the Netherlands?

Had contact with Curt, but I think he's not receiving my mails.

I'm really fond of this unit, HD support, more silent and (kinda) fits in the same space as my VPH-1041QM. Would be great to get this beast running all colours / colors

Boet · Joined: 10 Jan 2012 Posts: 30 Location: Netherlands

So, just to be clear: you have two input boards (IFB-12? and IFB-40). I've had a quick look into the schematics of those (and the VPH-1270).

You've tried the IFB-40, wired for RGB. I assume you've soldered the IFB-40 like on page 10 of the manual:
https://pro.sony/s3/cms-static-content/operation-manual/3858498031.pdf
No red.

IFB-12 -> no red over RGBHV.
And using composite, you DO get an image. But again only blue and green, no red?
This last check makes me very much doubt it's the input cards, since the composite video is connected to the R input and passes into the projector unaltered. Decoding the composite signal into RGBHV is handled deeper down into the projector, as well as the menu overlays.

Since the on-screen menu still works, the fault will likely be between the input board (but <after> the composite decoder) and the multiplexer (where the projector its internal signal and the external signals are mixed together).
This makes the BB board my first suspect in case of the VPH-1270.
See attached picture. Perhaps something faulty around Q673 - Q679. If that's the case, it shouldn't be too difficult. However, this is only an educated guess.

I don't have the schematics of the complete VPH-D50(QM) to dig deeper now, I also don't know the differences on circuit level compared to the VPH-1270. I've found the VPH-D50(QM) service manual for sale on a couple of websites though.

A board buried inside the set can be a pain to diagnose.
I've done such things the 'dirty' way before: solder wires to a couple of strategically chosen measurement points, put the board back in, and measure at those wires. Flatcable works wonders for this.

Where in NL do you live?

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Hi Boet,

I live in Lelystad, below sea-level. But I have a car and a drivers license Smile

Holland isn't that big.

I've figured out that input B is a IFB-40. Not sure how to determine if input A board is a IFB-12. Could send a photo of it.

Input B only had the DIN connectors (in and out), took the board out, used the schematics you mentioned, and soldered a VGA (to RGBHV) cable directly to the DIN connector (so the original input plug is gone now). I can get a picture, but no red. Only red I see is the on screen menu. the exact same result as with input board A.

I thought the problem would be with the input board. So I tried to use the other (B) board. The A board has a lot more input options, but composite (not component) as well as RGBHV give the same results (though different resolutions), on screen menu, test patterns give all colors, but the input picture is only green and blue.

**Curt Palme** · Posted: Fri May 15, 2020 3:38 pm Post subject:

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Hi Curt,

Could we try again?

kind regards

**Curt Palme** · Posted: Fri May 15, 2020 5:08 pm Post subject:

Sorry, maybe I misinterpreted. Can you email me again, all of your emails got deleted.
thanks!

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

No problem,I'll mail you in a second

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Hi Curt,

Received the package today, installed it at a hartbeat.

And yes, it works now! So a big thank you is in place.

Next up is mounting this beast to the ceiling.

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

So I finally had the time to mount this machine. Quite an upgrade from the 1041QM. However, the picture is just a bit too bright, and adjusting the brightness levels has no effect. for min to max. picture stays the same?

Any thoughts on this? Should I change the RGB input signal? Am I missing some setting?

**Curt Palme** · Posted: Sun Oct 18, 2020 2:44 pm Post subject:

It's possible that some capacitors have failed on the PA board, that drive the screen voltage. Was a common fault on many D50s that came through here. Or.. your screen and bias settings are set too high within the menus.

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

Thanks!

With service menu on, pressing bias button on remote shows me 111 for the rgb options, kinda between min and max.

With ‘set setting’ -> abg mode off, the brightness drops dramatically and I need to max the contrast to have a nice picture. Changing brightness has still no effect.

Kind regards

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

I found the bias settings, but where do I check the screen settings? Smile

**Curt Palme** · Posted: Sun Oct 18, 2020 8:21 pm Post subject:

In the service menu. Sorry, maybe it's called G2? I can't remember. Smile

jantino · Joined: 29 Apr 2020 Posts: 14 Location: Netherlands

ah to bad, no more settings to be utilized and setting brightness levels has no effect.

Where should i look for bad caps?

**Curt Palme** · Posted: Thu Oct 29, 2020 1:42 pm Post subject:

Check/replace the three 4.7uf capacitors on the PA board. They are all next to each other. This problem can also be caused by the tubes having different gains due to age, which throw off the AKB circuit.