Well, I just received my display boards.
I will be lucky if I can make 2 out of the 4 boards I got. I must be
fair and say that I ordered just 2 and the vendor sent me 4, but the
packing was... inappropriate. All of the boards were piled up one on top of
the other without any kind of separator, one layer of thin bubble wrap on
the bottom of the box, 2 or 3 on the top and that was it. Only one board
has both displays with vacuum in them (one of which was chipped in one of
its ends), which is not the same as saying that they are both working. Of
the remaining three, two had one of the displays without vacuum and the
last of them had one of the displays totally mashed. There were glass
pieces all over the place.
It makes me remind of the horror stories about the sale of NL7971s by
Poly-Pack (IIRC).
I have a strong suspicion that a couple of the displays were already
damaged before being packed. Besides, all boards show signs of attempted
repairs (mostly around the electrolytic caps) and spewed electrolyte, but
again to be fair the boards are being sold as untested and coming from an
bulk warehouse stock buy. We all know how wide is the definition of
untested.
Anyway, I plan to clean up the mess, apply 5Vcc to the TTL and HV power
supply lines, tie a microcontroller kit and check the status of the logic
and driver chips before deciding which boards become donors.
Regarding to which platform I would use... I have several NodeMCU ESP32
sitting in a box which I think with a little struggling or worst case
adding some glue logic can be used. WiFi configuration and NTP
syncronization would be cool. If this plan does not work, then my fallback
is Arduino nano as I also have several sitting in a box next to the
NodeMCUs :).
On Wednesday, September 25, 2019 at 2:05:15 AM UTC-3, Richard Scales wrote:
>
> That sounds promising - what would be your platform of choice? I can see
> that something like Arduino Mega or a Teensy would have the required i/o.
> I have no experience of doing anything with a multiplexed display, it all
> seems like magic to me!
>
> On Tuesday, 24 September 2019 21:47:24 UTC+1, GastonP wrote:
>>
>> Actually, the 8255 and an LS273, both through HV buffers, drive the
>> segments.Ports A and B of the 8255 drive the "upper" VFD anodes (+47V)
>> while Port C and the LS273 drive the "lower" VFD anodes (+47V).
>> The TL5812 drives the digit grids (one per digit) through a separate
>> serial shift register interface.
>>
>> It's a classic configuration for a multiplexed display, that can be
>> easily controlled by any modern microcontroller with 16 free pins without
>> recurring to specialized hardware. Just plain old parallel interface for
>> the segments plus a little bit-banging for the digits. If one wants to use
>> a processor with less free pins, it can be done too, but the complexity
>> grows.
>>
>> I just ordered a couple of this boards and am crossing my fingers...
>>
>>
>> On Wednesday, September 18, 2019 at 1:00:41 PM UTC-3, Keith Moore wrote:
>>>
>>> Richard, I have not yet done it, but I do plan to at some time. I got a
>>> few of these for various reasons (demo/display, etc.). I assume you have
>>> the detailed data / pinball instruction sheet like I do. If not, let me
>>> know.
>>>
>>> https://www.dropbox.com/s/bltgd4w4o9gonuy/Alvin_G_Display.zip?dl=0
>>>
>>>
>>> My chops aren't good enough to just whip out the electronics to drive
>>> these, but I was planning on making a computer that does this eventually.
>>> It is an IEEE 8255 interface. I should be able to do it with an arduino.
>>>
>>>
>>> On Tuesday, September 17, 2019 at 11:11:26 PM UTC-4, Richard Scales
>>> wrote:
>>>>
>>>> I was wondering whether anyone has had any success talking to the Alvin
>>>> G PCA-003 boards that are available:
>>>> https://www.pinballspareparts.com.au/electronics/displays/pca-003.html
>>>> <https://www.pinballspareparts.com.au/electronics/displays/pca-003.html?fbclid=IwAR2epmNiBA7UkcB1H0XqUivyeQEMSmN1HWyIhaM-oZXsEYUmPsewaJ0FLSw>
>>>> I would be interested to hear from anyone that has managed to talk to
>>>> one or who might be able to provide any insight into how their interface
>>>> works.
>>>> I have a few coming my way and would like to see if I can make them
>>>> talk somehow.
>>>> Any pointers to information about interfacing requirements and
>>>> protocols etc would be most welcome.
>>>>
>>>>
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