Mistake below, Vo should be a fraction of 5 volts, not "a volt" when
operating
On Fri, Jul 10, 2020 at 2:28 PM Ian Finder wrote:
> A few responses-
>
> On Fri, Jul 10, 2020 at 12:29 PM Brent Hilpert wrote:
>
>> Reading that datasheet, it appears that to reduce power consumption those
>> sensors
On 7/10/20 2:14 PM, Al Kossow via cctalk wrote:
There are a couple of serious researchers out there who do useful work, here is
what exists for the SD switch
https://deskthority.net/wiki/Micro_Switch_SD_Series
the schematic of the 1660 microswitch keyboard can be found on page 235 of the
ma
A few responses-
On Fri, Jul 10, 2020 at 12:29 PM Brent Hilpert wrote:
> Reading that datasheet, it appears that to reduce power consumption those
> sensors employ pulsed sleep/wake operation, presenting up to a 1/8 second
> delay in response time. Probably not very good for use in a keyboard, a
What type of computer is your friend restoring?
I don't think he wants to reveal that, and it shouldn't matter anyway.
There are a couple of serious researchers out there who do useful work, here is
what exists for the SD switch
https://deskthority.net/wiki/Micro_Switch_SD_Series
Hi Ian,
What type of computer is your friend restoring? I can't help as I have a
full keyboard that I'd like to keep intact but this is a home made
terminal/keyboard made from Diablo 1620 parts including the keyboard and I
believe the HyTerm main board. It has SD switches but they are mostly
4B
On 2020-Jul-10, at 11:27 AM, Ian Finder via cctalk wrote:
> On Fri, Jul 10, 2020 at 11:06 AM Al Kossow via cctalk
> wrote:
>>
>> Since it isn't very fancy, I wonder if you could make a new board with a
>> modern Hall
>> effect sensor? You just need a contact closure.
> Yeah Al, that's a great su
On 7/10/20 10:42 AM, Electronics Plus via cctech wrote:
I have a number of keyboards with Micro Switch ST switches, but no SD.
Does anyone still use old Memorex or Telex keyboards?
YES! I have terminals w/o keyboards
Yeah Al, that's a great suggestion. I was looking at the AH1815 last night.
The challenge is getting the whole assembly as thin as the original, which
presents a not insignificant challenge-
Even using the SOT553 package of this:
https://cdn.sparkfun.com/assets/4/4/8/2/a/AH1815.pdf - I'd have to d
ctech [mailto:cctech-boun...@classiccmp.org] On Behalf Of Ian
> Finder via cctech
> Sent: Thursday, July 09, 2020 11:34 PM
> To: classic...@classiccmp.org
> Subject: In search of 4B3A Microswitch Keyswitches (for a restoration, not
> a keyboard collector!)
>
> I know what yo
...@classiccmp.org
Subject: In search of 4B3A Microswitch Keyswitches (for a restoration, not a
keyboard collector!)
I know what you guys are thinking- no, this isn't for a keyboard collection
or some modern build or some other nonsense like that.
I have a friend who is restoring a fairly intere
On 7/10/20 9:45 AM, Al Kossow via cctalk wrote:
4B3A is a non-multiplexed contact closure type which is extremely difficult to
find.
Since it isn't very fancy, I wonder if you could make a new board with a modern
Hall
effect sensor? You just need a contact closure.
On 7/9/20 9:34 PM, Ian Finder via cctalk wrote:
The correct SD-series replacement switch would be the 4B3A-
It would be interesting to understand the failure mode. I wonder if they
passivated
the die correctly?
4B3A is a non-multiplexed contact closure type which is extremely difficult to
f
I know what you guys are thinking- no, this isn't for a keyboard collection
or some modern build or some other nonsense like that.
I have a friend who is restoring a fairly interesting and historically
significant vintage computer- a and subject to what appears to be a
batch-related encapsulation
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