Sony HB-F1 no keyboard input at all

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By Alexey

Guardian (1613)

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23-02-2018, 16:20

What are the resistance values of the slider in rightmost and leftmost positions?

By Dr.Wily

Rookie (18)

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23-02-2018, 17:00

Alexey wrote:

What are the resistance values of the slider in rightmost and leftmost positions?

- At full right : 16 ohm
- At fullt left : 48 kohm

It's the "speed controler" pot.

By gdx

Prophet (2217)

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24-02-2018, 09:15

Based on the latest tests, now I think the issue is caused by a poor contact. Check all the welds. Reweld all that seems dried up. Check also the conductivity of the wires.

By Dr.Wily

Rookie (18)

Dr.Wily's picture

26-02-2018, 12:15

OK, but where to start checking ? If the MSX freeze, what is the origin of that ? Z80, RAM ? Plus, there is a double layer of printed circuit on solder side that make diagnosis very difficult.

By Alexey

Guardian (1613)

Alexey's picture

26-02-2018, 13:07

Do you mean those additional blue tracks that are on top of the board? I heard that those are really easy to break and almost impossible to fix. Looks like one of them may be broken/cracked, so carefully inspecting it under a microscope and checking the continuity for the entire track would be advised.

I think fixing such broken track may be possible with a conductive glue, but only if the track is conductive on its top layer. Otherwise only putting a copper/alu wire will help.

By rderooy

Champion (330)

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26-02-2018, 12:34

By Alexey

Guardian (1613)

Alexey's picture

26-02-2018, 13:08

rderooy wrote:

time to put it into the oven :-)
https://makezine.com/2015/04/15/diy-open-source-reflow-oven/

Oh, that will ruin those blue tracks for sure IMHO.

By Dr.Wily

Rookie (18)

Dr.Wily's picture

26-02-2018, 13:09

Alexey wrote:

Do you mean those additional blue tracks that are on top of the board?

Yes, these tracks. These one are not conductive, I must scratch them to test... and it's not a good solution indeed.

By gdx

Prophet (2217)

gdx's picture

26-02-2018, 13:53

Do again all welds without thinking.
Several welds seem to have aged badly.

By Dr.Wily

Rookie (18)

Dr.Wily's picture

26-02-2018, 18:45

Is there a schematic diagram of the HB-F1 floating somewhere ?

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