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[令和二年九八月十八日(2020/09/18)]
PC110 XRレジスタ値 調べ   [to English Note

(表面が劣化した)FSTN液晶の劣化層を剥いで2枚の偏光板だけにした「nFSTN化 PC110」が使えるようになったので、今まで懸案だった、CRT(外部ディスプレイ)、STN、TFTそれぞれへの切り替えの為に設定すべき「(C&T 65535の)XRレジスタ」の値を調べてみた
DOSモードのみ。Win95などでは、全く違う値になるだろうと思うが、未検討)。

それぞれの状態から、他へ切り替えた時に"値が変化する項目"だけに絞り込んだ。(図2[クリック])
(流石に、)"CRT"と"STN"とで切り変わる項目は、5項目だけだが、"TFT"の場合は、18項目あった。ただし、Moonlightさんから指摘のあった"ドットクロック"を半分に落とす操作は、ここでは省略したので、それを入れると2〜3項目は増加する。XRレジスタ値.txt

"STN"と"TFT"とを、入力信号などで検出/識別出来れば、自動的に切り替えられるが、その方法を未だ思い付けていないので、手動で切り替える以外に、方法は無い。
更に、Win95,Win98などでは、これらの値の設定は、起動直後で、「Autoexec.bat」内で指定した後は、そのままの状態を維持するだけになる。
もし、OS側で変更した場合には、そちらが"優先"になってしまうようだ。
これについては、今後更に調べねばならない。

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+++ 「制御基板」の修理 +++

「制御基板」の修理には、先回表面実装用コンデンサ(中古品)を使ったが、数に限りがあったので、別途、小型縦型電解コンデンサ16μF/10Vを買ってみた。(図4[クリック])

しかし、そのまま立てて搭載すると、高さがオーバーするので、少し傾けねばならなかった。(図3)
横に寝かせて実装する方法もあろうが、あまりスマートではない。
本来の形のものだと、半田付けが、大変に難しいので痛し痒しだ。
(結局、最後は、表面実装用コンデンサをジャンク箱から探し出して来て、それらに置き換えた)

昔から、電源部の故障は、"コンデンサの劣化を疑え"と教わって来たが、なかなか気が付かないものだ。
此処の劣化を最初に発見された方は、偉い!と思う。
お陰で、私の作業も更に進められそう。


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[2020/09/18]
PC110 XR register value check   [to English Note ]

Since the "nFSTN PC110 ", which is made by stripping the deteriorated layer of surface of the FSTN liquid crystal and using only two new polarizing plates, can now be used.
Check the value of " XR register (of Chips65535)" that should be set for switching to CRT (external display), STN, and TFT, which was a concern. I tried
( DOS mode only.
I think that it will be a quit different value in Win95 etc., but it has not been examined).

From each state, I narrowed down to only " Items whose value changes " when switching to the other. (Fig_2 [click])
There are only 5 items that can be switched between " CRT " and " STN ", but in the case of " TFT " There were 18 items.

However, the operation of lowering the "dot clock" in half, which was pointed out by Mr. Moonlight , was omitted here, so if it's included it, 2-3 items will increase. " XR register value.txt "

If " STN " and " TFT " can be detected /identified by the input signal etc., they can be switched automatically, but I haven't come up with a method yet.
There is no other way, but to switch manually.
Furthermore, in Win95 , Win98 , etc., these values are set immediately after startup, "Autoexec.bat". After specifying it in, it just keeps it as it is.
When I change it on the OS side, it seems that it will be "priority".
We need to investigate this further in the future.

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+++ Repair of "control board" +++

Surface mount capacitors (second-hand parts) were used to repair the "control board", but the number was limited, so separately. I bought a small vertical electrolytic capacitor 16μF/10V. (Fig_4 [click])

However, if it was installed upright, the height would be exceeded, so I had to tilt it a little. (Fig_3)
I could lay it on its side and implement it, but it's not very smart.
It's painful and itchy because it's very difficult to solder in its original form.
(In the end, I searched for surface mount capacitors from the junk box and replaced them with them.)

It has been taught for a long time that a failure in the power supply section is "suspicious of deterioration of the capacitor", but it is hard to notice.
The first person to discover the deterioration here is great! I think .
Thanks to that, my work will be further advanced.


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