ホーム » 掲示板 » MSX Talk » Hardware » Sony HB-75P RGB out

Sony HB-75P RGB out

ページ 1/2
| 2

By QBee Sam

Champion (298)

QBee Sam さんの画像

19-05-2022, 15:24

I've been using RGB potenciometers to fix the blue image from my Sony HB-75P, now is better than the original but not much beter, there is some kind of trick, procedure or so to improve the image quality instead of try and error that I've did?

Original picture:

Current picure, a bit clear but not good, still blue:

Emulating with OpenMSX I get this, so far from real and not sure if is possible to improve even more:

ログイン/登録して投稿

By Jipe

Paragon (1625)

Jipe さんの画像

19-05-2022, 16:22

turn RGB potenciometers for obtain a very good white color and normally the other colors are good
on chapter 6 of the service manual you have the RGB ADJUSTEMENT by required an Oscilloscope

By Wierzbowsky

Guardian (3650)

Wierzbowsky さんの画像

19-05-2022, 17:35

The procedure is described in the service manual (Chapter 6, page 6-1 and 6-2). You need to trim a few pots using the oscilloscope. And this is major pain in the back because RGB test points are hidden under the huge radiator. One wrong move and it touches something on the motherboard. Besides, trimming should be done after color15,15 command, so the keyboard also needs to be temporarily connected. This doesn't make things easier.

By sdsnatcher73

Enlighted (4322)

sdsnatcher73 さんの画像

19-05-2022, 18:01

Which explains why they were supplied with such bad calibration

By Nprod

Expert (105)

Nprod さんの画像

19-05-2022, 19:23

Sort of off topic, but here's a reminder to change the RIFA filter capacitors on the pcb at the left side if you haven't yet.

By sdsnatcher73

Enlighted (4322)

sdsnatcher73 さんの画像

20-05-2022, 14:04

Why is that? Are they known to cause trouble? If so what kind of trouble Wink?

By QBee Sam

Champion (298)

QBee Sam さんの画像

21-05-2022, 18:24

Nprod wrote:

Sort of off topic, but here's a reminder to change the RIFA filter capacitors on the pcb at the left side if you haven't yet.

Oh, thanks.

By QBee Sam

Champion (298)

QBee Sam さんの画像

21-05-2022, 18:25

Jipe wrote:

turn RGB potenciometers for obtain a very good white color and normally the other colors are good
on chapter 6 of the service manual you have the RGB ADJUSTEMENT by required an Oscilloscope

I'll take a look, thank you!

By QBee Sam

Champion (298)

QBee Sam さんの画像

21-05-2022, 18:27

Alexey wrote:

The procedure is described in the service manual (Chapter 6, page 6-1 and 6-2). You need to trim a few pots using the oscilloscope. And this is major pain in the back because RGB test points are hidden under the huge radiator. One wrong move and it touches something on the motherboard. Besides, trimming should be done after color15,15 command, so the keyboard also needs to be temporarily connected. This doesn't make things easier.

This doesn't sounds easy for my knowlege, I have no osciloscope btw, so I'll try my best, thank you!

By Wierzbowsky

Guardian (3650)

Wierzbowsky さんの画像

22-05-2022, 16:44

One more thing - even with the installed and secured radiator please make sure that your screwdriver doesn't touch the terminals of the voltage regulators that are conveniently located very near the holes that lead to RBG pots. If you touch the radiator and one of the powered terminals, there will be fireworks.

By Wild_Penguin

Hero (644)

Wild_Penguin さんの画像

30-05-2022, 18:47

I'm not sure but no matter how well the calibration is done, it seems there will always be a slight blue tint on the HB-75P - but it could also be some components (capacitors?) have not aged well on my unit, or I've done the calibration incorrectly (I'm a self-learned hobbyist, after all). But the blue tint should not be that severe, it will still look decent, and I'll take it over any composite output any day.

ページ 1/2
| 2