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Building a Z80 MBC system [message #8909] Wed, 28 July 2021 05:14 Go to next message
edzard is currently offline  edzard
Messages: 64
Registered: August 2019
Member
Hello All,

Got a package in the mail today with all of the PCB's for a Z80 MBC system.

Keep you posted on the progress!


Kind regards,


Edzard

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Re: Building a Z80 MBC system [message #8918 is a reply to message #8909] Thu, 29 July 2021 12:19 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
Messages: 1080
Registered: June 2016
Senior Member
Hi Edzard
Awesome! Going with the all-black PCB theme. Looks good!

Thanks, Andrew Lynch

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Re: Building a Z80 MBC system [message #9047 is a reply to message #8909] Wed, 25 August 2021 11:48 Go to previous messageGo to next message
edzard is currently offline  edzard
Messages: 64
Registered: August 2019
Member
Hello All,

After a short vacation break I'm back at building/debugging.
Got the newest Z80 MBC PCB's so thought I would start with that first.

I searched through my bin and found a lot I could use, so I soldered away...

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Best regards,

Edzard
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Re: Building a Z80 MBC system [message #9048 is a reply to message #9047] Wed, 25 August 2021 12:02 Go to previous messageGo to next message
edzard is currently offline  edzard
Messages: 64
Registered: August 2019
Member
Some more boards,

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The 0 Ohm resistors are flown away...
Couldn't find some vertical capacitors too, so I ordered some.

I found some larger 10uF capacitors and, without thinking too much, I soldered them in.
Too large for the bus PCB..


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So I need to order some smaller too.


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I think when al is working I will try to make smaller extendable Bus PCB (1 or 2 connectors removed).
Like the http://linc.no/products/z50bus-5-slot-backplane/
Within the 10x10 cm boundary.

Thanks for al your work Andrew!



Best regards,

Edzard
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[Updated on: Wed, 25 August 2021 12:02]

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Re: Building a Z80 MBC system [message #9049 is a reply to message #9048] Wed, 25 August 2021 12:12 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
Messages: 1080
Registered: June 2016
Senior Member
Hi Edzard
Looks great! Good luck in your build!

Thanks, Andrew Lynch

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Re: Building a Z80 MBC system [message #9064 is a reply to message #9049] Mon, 30 August 2021 08:11 Go to previous messageGo to next message
edzard is currently offline  edzard
Messages: 64
Registered: August 2019
Member
Hello All,

Finished soldering all boards. Started testing the boards for voltage.

It's a nice touch that each board has a LED for this purpose.

I've already have a stable 5V - 10A power supply so I shortend the LM7805 circuit on the Back plane board.
(my first Back plane board had a LM7805 installed, but with a normal standard 5V Wall transformer the voltage drops below 5V. And I couldn't find one with a higher Voltage in my toolbox)


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Best regards,


Edzard
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Re: Building a Z80 MBC system [message #9065 is a reply to message #9064] Mon, 30 August 2021 08:31 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
Messages: 1080
Registered: June 2016
Senior Member
Hi Edzard
Looks great! I am finding a lot of people like to use 5v DC direct from power supply and bypass the voltage regulator. So the next Z80 backplane PCB will include screw terminals to allow direct wiring of 5v DC regulated from a power supply. Wall adapters are convenient if you move the system around but a lot of people are building them on their benches and have power supplies available. Makes sense to use them.

Thanks for the photos! Andrew Lynch

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Re: Building a Z80 MBC system [message #9077 is a reply to message #9065] Wed, 01 September 2021 08:00 Go to previous messageGo to next message
etchedpixels is currently offline  etchedpixels
Messages: 333
Registered: October 2015
Senior Member
USB 5v to the usual jack connector cables are available in bulk and really cheap so that might also be a good option as most USB supplies are a really clean stable 5v.

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Re: Building a Z80 MBC system [message #9080 is a reply to message #9077] Wed, 01 September 2021 08:43 Go to previous messageGo to next message
edzard is currently offline  edzard
Messages: 64
Registered: August 2019
Member
Hello All,

Managed to get all parts on the PCB's. Next step is to get all the jumpers right and program the EPROM..Smile

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Are there any things I have to wacht/look out for?



Kind regards,


Edzard
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[Updated on: Wed, 01 September 2021 11:25]

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Re: Building a Z80 MBC system [message #9083 is a reply to message #9080] Wed, 01 September 2021 11:55 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
Messages: 1080
Registered: June 2016
Senior Member
Hi
Looks great!

A couple of things, first I would test each board in the backplane separately and check out VCC & GND before testing them together. Second, I would make sure the TTL oscillators are soldered directly to the PCB or at least covered with an insulator so they don't cause board to board shorting.

You are actually ahead of me now since my Z80 processor V2, Z80 serial V2, and Z80 DMA PCBs just arrived. Will start building them this weekend.

Thanks, Andrew Lynch

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Re: Building a Z80 MBC system [message #9084 is a reply to message #9083] Wed, 01 September 2021 12:14 Go to previous messageGo to next message
edzard is currently offline  edzard
Messages: 64
Registered: August 2019
Member
Hello Andrew,

Will do some VCC/GND testing.

The pin headers I've used are pretty long (longer then a socket oscillator) and almost touch the PCB in front of them. So these a my biggest concern for shortening the circuit when touching the PCB's. I think I will clip a few mm off.

Thanks again,

Best regards,


Edzard

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Re: Building a Z80 MBC system [message #9088 is a reply to message #9084] Thu, 02 September 2021 03:30 Go to previous messageGo to next message
lynchaj is currently offline  lynchaj
Messages: 1080
Registered: June 2016
Senior Member
Hi Edzard
When I built my Z80 MBC I did it in phases. Start with the Z80 backplane and power up. Check the pins with VOM. Then add Z80 processor board and do the same. Add the Z80 clock board, repeat. Add the Z80 ROM board. Now you should see some activity depending on what ROM image you are using. I would expect to see LEDs flashing and possibly the speaker beeping with RomWBW. If your Z80 clock board speaker is too quiet try placing a 10K ohm resistor across the terminals of the piezo speaker on the back of the PCB. For some reason that seems to help with audio loudness.

An incremental approach will help you isolate problems easier and fix them as you find them. Hopefully there aren't any problems but if there are any it will help.

Good luck! Thanks, Andrew Lynch

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Re: Building a Z80 MBC system [message #9119 is a reply to message #9088] Fri, 10 September 2021 05:10 Go to previous message
lynchaj is currently offline  lynchaj
Messages: 1080
Registered: June 2016
Senior Member
Hi Edzard
How is your Z80 MBC build coming along? Well I hope

Thanks, Andrew Lynch

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