VOGONS


XT/CGA laptop dissection

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Reply 100 of 103, by Jonas-fr

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mattinx wrote:

If there's anyone else out there with a Victor V86P that has a dead (or missing) PSU and wants to use an existing 8.5V PSU (like the one for the Playstation2 suggested earlier), I've reverse engineered the battery charging circuitry that's in the original PSU, and made a little board to implement it:
http://pkl.net/~matt/charger-board4.png
I'm still waiting on getting the board back, and I need to rebuild the battery pack (it's a stack of Sub-C NiCd cells in a cardboard tube with a couple of thermal cutouts) - so I don't actually know if the board works yet, but the idea is that you have a barrel jack input that'll take the output from a generic 8.5V brick, and it'll give you the necessary power and signalling for the V86P's charge circuitry.

Hi,

I just got a Victor V86P in a fairly good condition from a dumpster yesterday. Sadly it came without any PSU nor battery so I cannot test it atm. I'll be interested into your circuit but I don't get why it's using a non standard/harder to find 8.5V charger for input and not a regular and widely available 9V or even 12V one, could you elaborate on this choice ?

Reply 101 of 103, by tifan

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Jonas-fr wrote on 2019-02-17, 13:18:
mattinx wrote:

If there's anyone else out there with a Victor V86P that has a dead (or missing) PSU and wants to use an existing 8.5V PSU (like the one for the Playstation2 suggested earlier), I've reverse engineered the battery charging circuitry that's in the original PSU, and made a little board to implement it:
http://pkl.net/~matt/charger-board4.png
I'm still waiting on getting the board back, and I need to rebuild the battery pack (it's a stack of Sub-C NiCd cells in a cardboard tube with a couple of thermal cutouts) - so I don't actually know if the board works yet, but the idea is that you have a barrel jack input that'll take the output from a generic 8.5V brick, and it'll give you the necessary power and signalling for the V86P's charge circuitry.

Hi,

I just got a Victor V86P in a fairly good condition from a dumpster yesterday. Sadly it came without any PSU nor battery so I cannot test it atm. I'll be interested into your circuit but I don't get why it's using a non standard/harder to find 8.5V charger for input and not a regular and widely available 9V or even 12V one, could you elaborate on this choice ?

I have the original schematics for Victor V86p clone. The machine was relicensed to another Chinese company and was made into a portable word processor.

Link: https://software-archive.tifan.la/Stone-Chine … 86%E5%9B%BE.pdf start from page (PDF page number) 233

Reply 102 of 103, by mattinx

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Jonas-fr wrote on 2019-02-17, 13:18:

I just got a Victor V86P in a fairly good condition from a dumpster yesterday. Sadly it came without any PSU nor battery so I cannot test it atm. I'll be interested into your circuit but I don't get why it's using a non standard/harder to find 8.5V charger for input and not a regular and widely available 9V or even 12V one, could you elaborate on this choice ?

Totally forgot this thread existed, and in case you're still wondering - 8.5V is what the original PSU generated, and my board is literally just the NiCd charge circuitry - I'm not adding any additional regulation, which is why it needs an 8.5V input.

On a related note, I'm actually most of the way through overhauling the power system to allow the system to run from a pair of Li-Ion 18650 cells - they fit neatly in the existing battery compartment with enough space for an off the shelf battery protection board. I've got a new spin of the charger board with a Li-Ion charge control IC on board, and I just need to look at replacing the power input board in the system itself so it's possible to properly charge when the system is powered on. If I remember correctly (project's been on the back-burner for a year or two now) I got about two hours runtime from a pair of 18650s.

There's also https://github.com/hennichodernich/v86p-ide which was developed by https://radiosocial.de/@hennichodernich on top of some of the reverse engineering work I did on the system. I've put one of those boards in my system along with a CF reader, and it works incredibly well.

I need to write up all the work I've done on this thing to date and get it up online.

Reply 103 of 103, by mattinx

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Finally picked back up with documenting some of the work I've been doing with my V86P. Here's the write-up for the ISA backplane I put together: https://knm.org.uk/blog/2024/03/working-on-th … -expansion-bus/

I've got a few more drafts written, and a folder full of photos - I just need to do a little editing and there'll be more coming up soon.