Sony HB10 / HB20 Hardware issue + fix

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By gdx

Prophet (3483)

gdx's picture

22-04-2017, 09:49

Thanks to Metalgear2. I add the link in Sony HB-20P wiki.

PS: This tutorial moves the RAM to Slot 3 (instead of slot 0 with mirror in slot 3).

By cochecito

Resident (51)

cochecito's picture

25-04-2017, 09:49

sd_snatcher wrote:

@ericb59

Sony engineers seem to have added that diode there to protect the chipset against badly constructed cartridges that try to reset the MSX via slot, which is incorrect and will indeed damage many machines (i.e.: the NMS-8245). I haven't seen any commercial cartridges that do this, so it's more like a protection against hobbyist experiments.

Hi.

Please, Could you explain more about that problem with the NMS 8245?

ThanksThat's!

By saez05

Expert (111)

saez05's picture

13-05-2017, 15:26

Another mysterious difference of Sony hb 20 and 10
Hello, I have tried the modifications for the hb20 to see if it solved what happens to me. The same cartridge I have from a konami compilation on the hb10 goes well but on all the hb20 I tested it as wrong, as in the photo ... although it works out as well as a game works correctly, it seems that only the load menu Of the different games.
Well, it's still the same after putting the r15, the port mod # A8 and the 20 diode for a resistor, so I guess it still exists to discover ... I do not know if anyone has happened something like that.

By mzoran

Rookie (27)

mzoran's picture

30-05-2020, 13:44

I have a HB-10P that needs some work on it. I planned on doing all these changes but have also noticed that colors are really overly saturated on AV output and there is plenty of bleeding. Compared to Philips VG8020 this machine seems to have a different pallette Smile
Are the above changes having any effect on that, and if not, has anyone noticed the same problem ?
Thanks

By sd_snatcher

Prophet (3270)

sd_snatcher's picture

30-05-2020, 14:58

I have a HB-20P, and its colors seem perfectly normal. Yes, the Toshiba palette is a bit different from the Texas VDPs, but nothing offensive.

But the HB-20P had no native composive-video output, so I copied the missing components from a Japanese HB-10. Maybe it's on this specific part of the circuit that there's a problem on the HB-10P?

These were the components I copied from the HB-10 to the HB-20P (credit: WernerKai)

R7 = 1K
R8 = 47R
R9 = 10K
R12 = 6K8
R53 = Empty
C62 = 1nF
CN1/CN2 = A/V connector

Try to check if they have the same values on the HB-10P.

By sd_snatcher

Prophet (3270)

sd_snatcher's picture

30-05-2020, 15:03

saez05 wrote:

Another mysterious difference of Sony hb 20 and 10

Did you test it on a HB-10, or HB-10P?

By mzoran

Rookie (27)

mzoran's picture

30-05-2020, 23:42

@sd_snatcher: according to the service manual and a physical check I do have R53 of 1K. Also R7 measures at 0.7K, so under tolerance. Think I'll start by replacing it....
Thanks

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