Looking for MBP Clock/ADC photos

[Shift838]

I’m looking for photos of the MBP and MBP-II front and back.

 

anyone have the photos or a card you can snap some pics for me?

[RickyDean]

Here's am MBP.

[Shift838]

29 minutes ago, RickyDean said:

Here's am MBP.

 

 

What's the slide switch for on the back and what chip is piggybacked and for what ?

[RickyDean]

Can't give those answers, as I got this when I was with the Hoosier User Group. Haven't ever used it. Has been stored with all other stuff for 20 years, just came out 2 years or so ago. Don't know if I have any documentation either.

[RickyDean]

9 minutes ago, Shift838 said:

What's the slide switch for on the back and what chip is piggybacked and for what ?

The switch seems to tie  into a trace that goes under the clock chip to pin 3 and the other end of the trace ties into pin 16 of the 244 on the front left side and back right side of the board.

[+Ksarul]

This stuff might help. . .

MBPII.pdf mbp clock schematic and hardware manual.pdf

[RickyDean]

If I remember correctly this board belonged to Bill Lucid. I can test the covered chip with my ttl chip tester tomorrow and discover it's identity, if the chip is good.

[+InsaneMultitasker]

If I recall correctly, the switch is used to inhibit writes to the clock chip once the time/date are set.  

[+Schmitzi]

MBP-II

 

 

[Shift838]

42 minutes ago, Schmitzi said:

MBP-II

No clock chip?  What’s the chip that is piggy backed on yours?  Would be nice to know what all the jumper wires are from and going to.  

[+Schmitzi]

2 hours ago, Shift838 said:

No clock chip?  What’s the chip that is piggy backed on yours?  Would be nice to know what all the jumper wires are from and going to.  

 

Sorry it´s just an old pic from the internet... I don´t have the card

 

[RickyDean]

10 hours ago, Shift838 said:

What's the slide switch for on the back and what chip is piggybacked and for what ?

I would say, after looking at the pic, @Schmitzi posted. that my covered chip is a 74ls138. Schmitzi's covered chip may be another 74ls08, but the schematics that were posted should clarify that. Since Dan's name in on the back of the card, he might have intimate knowledge of this design.

[+InsaneMultitasker]

3 hours ago, RickyDean said:

I would say, after looking at the pic, @Schmitzi posted. that my covered chip is a 74ls138. Schmitzi's covered chip may be another 74ls08, but the schematics that were posted should clarify that. Since Dan's name in on the back of the card, he might have intimate knowledge of this design.

My first thought was that the extra chip is for AMA/B/C but it is too hard to verify from my phone    this card might be what Bill had in the HUG BBS system.

[Shift838]

3 hours ago, InsaneMultitasker said:

My first thought was that the extra chip is for AMA/B/C but it is too hard to verify from my phone    this card might be what Bill had in the HUG BBS system.

Looking at the photo I don't think it is the AMA/B/C modification to make it compatible with the Geneve.  We really need to know what the chip is under the piggy backed LS08.  The RED wire is hooked from Pin #1 of the piggy backed LS08 to pin #12 of the LS138 which is IC9.  The YELLOW wire is hooked up from Pin #2 of the piggy backed LS08 to pin #15 of the same LS138 IC9.  This mod also requires some traces to be cut as well and i do not see those.  Finding out what is under the LS08 may help but that would require desoldering it.

 

It also is not the modification to slow the clock down for the ADC to make it compatible with the Geneve as well.  

 

 

 

[Shift838]

Besides the 2 modifications that are documented in the MBP-II manual what other mods are there and what did they do?  The on/off switch that was mentioned earlier in this post sounds like a good mod.  Is there any documentation on it?  If not I would really need to see a hires photo of the card that @RickyDean snapped as it's too hard to see.  but then again, the version he has is the MBP and not the MBP-II.  was the issue corrected on the MBP-II already?

 

 

[RickyDean]

5 hours ago, Shift838 said:

Besides the 2 modifications that are documented in the MBP-II manual what other mods are there and what did they do?  The on/off switch that was mentioned earlier in this post sounds like a good mod.  Is there any documentation on it?  If not I would really need to see a hires photo of the card that @RickyDean snapped as it's too hard to see.  but then again, the version he has is the MBP and not the MBP-II.  was the issue corrected on the MBP-II already?

 

 

 

 

The switch enables, disables the WR line, pin 3 on the clock chip. Both wires are soldered on the same trace and there is a cut across the trace, between the wires. I tried testing the ic under the 138, but it tested bad. But looking at the chip underneath, it seems to be a 74ls13

[Shift838]

so i figured out what the mod was from @Schmitziphotos provided.  I thought I read the whole MPBII manual.  I missed the last page.  it's there!

 

This mod enables the Digital output for the ADC

 

[+dhe]

I remember Mac in Memphis, he's a really nice guy.

 

Dan's name is on the MBP-II board, because Dan really likes the MBP - it's a card so simple, even I could put one together and can be used from XB through assembly language.

 

At the time (early '90's) the folks that had been making it didn't want to do that thing anymore. I called Jerry McClusky and asked it I could buy the rights to reproduce the board. He had me send him a couple of hundred dollars and he gave me the rights to reproduce and sent me some PCB film that looked like:

 

 

Don Walden took the film, and re-did everything in cad/cam software, added fixes, enhancements and solder mask and birthed MBPII (or son of MBP).

 

 

 

[+dhe]

Ricky, in response to the ls13, Bill wrote back thus:

 

----------------

Good Evening Dan,

 

Do you have a schematic?   Silly question...  I do not remember all the wire-wrap wiring.  Maybe an early production board.

 

You likely already have this information:

The MBP card

MBPII

 

74LS13 appears to be a Scmitt trigger/hex inverter;  is it being used in place of a 73LS138 3 to 8 Line Decoder?

 

Can not imagine this board being used with Hugger BBS; although I have no real  clear recall of what was used for time/date stamping.

I do sort of remember speech syn. writing to clock chip...  reason for switch...

Good luck on restoring MBP card to operation!

 

Bill

[RickyDean]

58 minutes ago, dhe said:

Ricky, in response to the ls13, Bill wrote back thus:

 

----------------

Good Evening Dan,

 

Do you have a schematic?   Silly question...  I do not remember all the wire-wrap wiring.  Maybe an early production board.

 

You likely already have this information:

The MBP card

MBPII

 

74LS13 appears to be a Scmitt trigger/hex inverter;  is it being used in place of a 73LS138 3 to 8 Line Decoder?

 

Can not imagine this board being used with Hugger BBS; although I have no real  clear recall of what was used for time/date stamping.

I do sort of remember speech syn. writing to clock chip...  reason for switch...

Good luck on restoring MBP card to operation!

 

Bill

Thanks Dan, good to hear that Bill's still around! Yes in this particular case it seems to be in the same socket where a ls138 would reside. Then a ls138 is piggy backed on top, but for a different purpose.