Any differences with the Sony A2106R and H7240AKV encoders?

[StevieGoodwin]

I have an SCPH-7501 made August 1998 with U68 serial number and when i noticed when i use Composite with a Small Durabrand CRT TV and when it's at the Black PlayStation logo, I noticed that the red was more vivid and on the Sony A2106R and PSone, The Red was more of a pinkish color and how rare is the H7240AKV? I can commonly find the Sony A2106R. Also i did find an SCPH-7001 with that H7240AKV encoder and colors were vivid. Is there a way to find a console with the H7240AKV

[Orion_]

composite signal is really the worst video signal.
you should try to find an RGB scart TV, you will get the best picture for the PS1

[nocash]

I wasn't aware of the H7204AKV, but Sony had used a bunch of different RGB/composite chips, with the H7204AKV included:

Code: Select all

  IC207 64pin "SONY CXD2923AR" VRAM Data to Analog RGB         ;\oldest
  IC501 24pin "SONY CXA1645M" Analog RGB to Composite          ;/
  IC202 44pin "Philips TDA8771H" Digital RGB to Analog RGB     ;\old boards
  IC202 44pin "Motorola MC141685FT" Digital RGB to Analog RGB  ;/
  IC?   48pin "H7240AKV" 24bit RGB to Analog+Composite         ;-SCPH-7001?
  IC502 48pin "SONY CXA2106R-T4" 24bit RGB to Analog+Composite ;-newer boards

H7240AKV and CXA2106R seem to have the same pinout (except, I've listed pin7/pin8 swapped for CXA2106R in psxspx.htm, but that might be a mistake on my side). The chips might be different internally, or they might be exact same. In latter case, color differences would be related to external capacitors/resistors.

M y overall impression of the PSX color palette is that it uses a weird RGB intensity ramp, for example, 00:00:00 and FF:FF:FF are black and white, and 01:01:01 should be very-dark gray, but PSX games look better when raising the intensity, making 01:01:01 a bit brighter than very-dark. Though I don't have a TV receiver and can't compare the brightness of PSX pictures with "standard" TV pictures, so I am not sure if the PSX hardware is really brighter (or if the game/software is darker).

And if Sony has produced hardware with different RGB intensity ramps, then the hue of the colors could also change (eg. 40:40:C0 might look like 60:60:D0 on another console), no matter if using RGB or composite cables. But the red in the PS logo, isn't that plain red (without green/blue)? Theoretically, that shouldn't become pinkish, unless the RGB-to-composite conversion went wrong badly.

I've never seen a reason to use RGB cables for PSX, the (PAL-) composite signal looks good to enough to me (much better than SNES or C64 composite signals).

[rama3]

A pink hue hints at issues with the subcarrier clock. Compare this with some Super Nintendos or NES, where you can clearly see Composite artifacts being pink.
In any case, this is almost surely a slight problem with external components, as nocash said. This isn't fixable without lots of trial and error, and by then, you will have ruined the mainboard from the soldering experiments.
Best to just check a few different consoles and pick the one where it looks best.

By the way, Composite is my preferred signal when the game uses lots of dithering. I will chose it over RGB then any time.

[StevieGoodwin]

I'm about to open up my SCPH-7501 with the H720 video encoder and 9001 with 2106 encoder so i can find the subcarrier clock differenecs. Where can i find it in the 750x-900x board and what IC number is it? Also my H720 chip on my SCPH-7501 says 833 153. And now i opened up the SCPH-9001 and the 2106 chip says 944 HW1V. And oh, The SCPH-9001 has not been modded.

[nocash]

Check the datasheet for the H7240AKV.

[rama3]

We can only speculate about the exact details, but Sony surely didn't design the hue difference into the machine. When I said there might be differences between consoles, I meant aging related changes in the parameters of capacitors and resistors. You can't just "see" those by eye.
Does your TV have a HUE setting maybe?

[TriMesh]

I don't think there is any significant difference between them. Based on the (rather large) number of these consoles I have seen the choice of which chip to use seems to be basically random. It's not based on territory or even in any clear manner on the manufacture date. I have also at one point tried swapping the parts between boards, and could not see any performance differences (either on a monitor or a waveform scope).

I think it's quite possible that a "CXA2106R" is really just a Sony branded version of the Rohm BH7240AKV.

Another interesting thing is that in the SCPH-9000 series service manual that's on the net the section of the schematic that contains this part (on page 11) identifies it as "IC502 BH7240AKV-E2", but in the parts list (on page 20), the listing for IC502 says "CXA2106R-T4". This very strongly suggests that as far as Sony are concerned they are the same part.

[StevieGoodwin]

I can send pictures if you want me to:

Console Bottom:
Serial reading U6853474
https://s25.postimg.org/jdldznzrj/IMAG0043.jpg

Console Inside:
(The Power supply was it's original one and it was swapped with a red LED. I have a new PSU in it now)
https://s25.postimg.org/uegj4os0f/IMAG0044.jpg

Board:

https://s25.postimg.org/bbx5hrgzz/IMAG0049.jpg



Look at the differences between the Main Menu font smooth on both the 7501 with the vivid and the 9001 that is not vivid.


7501: https://s25.postimg.org/olb2hv5qn/IMAG0056.jpg

9001: https://s25.postimg.org/ilnbe7ky7/IMAG0057.jpg

Notice any differences?

Do you know what component probably aged on my SCPH-7501 to have this good picture? Because i bought an SCPH-7001 PU-20 that had the same picture as my 7501 and the same H720 encoder.

[rama3]

Try to find a trimmer capacitor around 30pF, such as these:
http://www.ebay.de/itm/Trimmkondensator ... 1622230498
Then install it in parallel with C523 from this picture:

I recommend you use 2 short wires to do this, as the capacitor is tiny and you wouldn't be able to turn the trimmer if you soldered it on directly.

The new capacitor will have variable capacitance that is a bit greater than the stock 33pF.
You can now adjust the Luma Trap filter offset and make the picture softer. If you wanted to make it sharper, you would have to desolder C523 and replace it with your trimmer capacitor.

Please note that this requires good soldering skills.
If you're not confident in applying and undoing this mod, leave it alone.
Just use the nicer looking console.