! Standby alert !
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
Looking forward to summer in Somerset later in the year :)
Very nice :)
Just wanted to make a suggestion about the notch on the connector. Melting the plasting and inserting this metalic rod isn't pretty.
I'm using a small square piece of veroboard and stick it in there with superglue. The thickness of it fits exactly.
It was just an observation really as the original does not, its academical anyway now as you have a joystick port already, and the MF128 does work with the +D so all good, just wondered really (poking about in memory etc!)
It was just an observation really as the original does not, its academical anyway now as you have a joystick port already, and the MF128 does work with the +D so all good, just wondered really (poking about in memory etc!)
you could always use the plus d hacker if you want to poke about in memory
All faults found and fixed, so ready for mass production ;)
1. Small design error: connected D0 to CPLD pin instead of D1 - small wire fix on production board of first batch
2. no stable 8 MHz from clock circuit: replaced 33pF capacitor by another ceramic type, problem solved
3. /IP from WD1772 was shortcircuited to ground on this specific assembled board, costed a little time to find, but solved
As I want to sell the PlusDlite with dual floppydrive set, I'm looking for a solution for one other problem: the cheap Chinese 5V power supplies cause some distortion at the ZX Spectrum's video output.
Better switching power supplies do not cause this.
So I wonder if it's possible to fix this by e.g. using a large capacitor (or maybe it should be a small one because it's a high frequency ripple) inside the floppydrives, or just find better power supplies.
Next week I'll have the anwser and get more boards assembled.
Screenshots coming up too!
A good quality low ESR electrolytic (say 470uF or 1000uF) in parallel with a 100nF capacitor may help, but to really clean up the supply you need a suppression choke (the type that has two windings, one winding for the +5V line and one for the 0V line). Follow it with a 220uF electrolytic in parallel with a 100nF capacitor. Of course, to be most effective, you need to tune the filter to the unwanted frequency...
Having said all that, it is also possible that some RF interference will be transmitted from the PSU via the connecting cable and will radiate through the air to the video lead or to the video circuits.
! Standby alert !
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
Looking forward to summer in Somerset later in the year :)
I did some testing yesterday, but I can't get the distortion problem go away by the use of (normal) capacitors.
I tried a 1000uF and 100nF in parallel close to the floppydrive power connector, but there was no difference.
Will try to find a solution lateron.
But I found another problem.
This problem was also present in the prototype with CPLD, and even in the original PlusD clone I got from Sintech in Germany with default GAL.
The problem is that when the ZX Spectrum has finished booting, and I type 'RUN' to load the systemfile and start the 'AUTOLOAD' file on disk, that sequence is not always completed succesfully.
Often the process stops/hangs after loading the system file.
The border is red then, and something on the PlusD is paged in (as the led is off), but nothing happens and BREAK doesn't work.
So I have to reset the system, and then find the system file is loaded because all commands work properly.
After that everything seems to work as it should.
It looks like some kind of signal timing problem, maybe something with paging of the ROM or WD1772.
Or maybe something with the clock circuit.
I have used 74LS type chips only, so even for the 74LS00 that is used in the clock circuit, and 74LS126 that is used for the DS0, DS1 and SIDE signals on the floppy connector.
Could it be that one of these should be another type, like CMOS?
I will add some leds to visually see which chip is paged, maybe that gives a clue to the problem.
One other thing I'm thinking of is to use UNI-DOS instead of G+DOS, as it's more advanced.
Is there any reason why I shoudn't?
RF distortion: indeed caused by a bad video cable.
Booting bug:
- tried 74HCT00 instead of 74LS00 for the clock circuit: no difference
- tried different power supplies and even one 5+12V supply to feed the ZX Spectrum and floppydrive
- tried extra capacitors on the pcb (close to ROM and SRAM) to find out if it's some power glitch
No solution sofar.
My next attempts:
- trying if UNI-DOS makes a difference
- getting a PlusD from a frient to check circuit differences (as the problem also occurs with the PlusD clone from Germany, with GAL)
- adding some paging leds on SRAM, ROM and FDC to find out if there is a paging error or give a clue of what is going wrong, and then maybe get my oscilloscope (an old one) for more detailed analysis
! Standby alert !
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
Looking forward to summer in Somerset later in the year :)
Tactically clever you did not comment on bundle prices or introductory offers [or even WoS discounts] ;-)
Anyway, this looks very good. Did you have a chance to think about a case? The +D had its cons, but the massive case was great, I think.
Tactically clever you did not comment on bundle prices or introductory offers [or even WoS discounts] ;-)
Anyway, this looks very good. Did you have a chance to think about a case? The +D had its cons, but the massive case was great, I think.
Hmmm, I still think cases are a handfull of work.
You must know it already costs a lot of time to do the development of such a new interface, to order parts and to assemble the whole.
If there would be someone who would specialise in building cases for several interfaces...
E.g. Kempston Joystick (I made 3 different versions already: 2012, 2012.2 and 2013), Kempston Mouse Turbo (2005, 2008 and 2011 versions), PC Keyboard Interface (2008 and 2013 upcoming), DivIDE (57C, 2K11), DivMMC, PlusDlite (v1, v1.1), Space Invader Kempston Joystick interface, etc.....
So there is enough work for one person to focus on....
Who is willing to make a living out of this (yeah, that's an invitation from this community)? ;)
Just an idea: when you want to make cases, and deliver one or two of each type to me, I will send you the interfaces for which they are needed.
You can sell the cases separately (mailbox delivery, so cheap) or sell me a ready made batch if there is still some profit left for you.
Sure, creating cases would mean a lot work and you?re already fairly busy. Maybe someone is willing and able to work on that or finds out by coincidence that a standard ready-to-buy one fits with only some little modification.
Hmmm, I still think cases are a handfull of work.
You must know it already costs a lot of time to do the development of such a new interface, to order parts and to assemble the whole.
If there would be someone who would specialise in building cases for several interfaces...
E.g. Kempston Joystick (I made 3 different versions already: 2012, 2012.2 and 2013), Kempston Mouse Turbo (2005, 2008 and 2011 versions), PC Keyboard Interface (2008 and 2013 upcoming), DivIDE (57C, 2K11), DivMMC, PlusDlite (v1, v1.1), Space Invader Kempston Joystick interface, etc.....
So there is enough work for one person to focus on....
Who is willing to make a living out of this (yeah, that's an invitation from this community)? ;)
Just an idea: when you want to make cases, and deliver one or two of each type to me, I will send you the interfaces for which they are needed.
You can sell the cases separately (mailbox delivery, so cheap) or sell me a ready made batch if there is still some profit left for you.
I'd be happy to look into the possibilities of fulfilling an order for case for this or other projects provided order quantity is a bit more than just the odd one or two. I'm sure there'll be some good demand for this though so I doubt numbers will really be an issue in this case.
Comments
I hope your bug hunting goes well.
Mark
Repair Guides. Spanish Hardware site.
WoS - can't download? Info here...
former Meulie Spectrum Archive but no longer available :-(
Spectranet: the TNFS directory thread
! Standby alert !
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
Looking forward to summer in Somerset later in the year :)
Just wanted to make a suggestion about the notch on the connector. Melting the plasting and inserting this metalic rod isn't pretty.
I'm using a small square piece of veroboard and stick it in there with superglue. The thickness of it fits exactly.
doubtful as its just a updated remake of the original interface using the original rom code so the ports will be the same
Why not? There is a version of the Multiface that works fine with the PlusD.
And I will start on the Multi Multiface soon anyway ;)
I was wondering: what do you want to use the Multiface for anyway, as the PlusD has a snapshot function embedded itself?
you could always use the plus d hacker if you want to poke about in memory
1. Small design error: connected D0 to CPLD pin instead of D1 - small wire fix on production board of first batch
2. no stable 8 MHz from clock circuit: replaced 33pF capacitor by another ceramic type, problem solved
3. /IP from WD1772 was shortcircuited to ground on this specific assembled board, costed a little time to find, but solved
As I want to sell the PlusDlite with dual floppydrive set, I'm looking for a solution for one other problem: the cheap Chinese 5V power supplies cause some distortion at the ZX Spectrum's video output.
Better switching power supplies do not cause this.
So I wonder if it's possible to fix this by e.g. using a large capacitor (or maybe it should be a small one because it's a high frequency ripple) inside the floppydrives, or just find better power supplies.
Next week I'll have the anwser and get more boards assembled.
Screenshots coming up too!
Having said all that, it is also possible that some RF interference will be transmitted from the PSU via the connecting cable and will radiate through the air to the video lead or to the video circuits.
Do let us know how you get on ;-)
Mark
Repair Guides. Spanish Hardware site.
WoS - can't download? Info here...
former Meulie Spectrum Archive but no longer available :-(
Spectranet: the TNFS directory thread
! Standby alert !
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
Looking forward to summer in Somerset later in the year :)
I tried a 1000uF and 100nF in parallel close to the floppydrive power connector, but there was no difference.
Will try to find a solution lateron.
But I found another problem.
This problem was also present in the prototype with CPLD, and even in the original PlusD clone I got from Sintech in Germany with default GAL.
The problem is that when the ZX Spectrum has finished booting, and I type 'RUN' to load the systemfile and start the 'AUTOLOAD' file on disk, that sequence is not always completed succesfully.
Often the process stops/hangs after loading the system file.
The border is red then, and something on the PlusD is paged in (as the led is off), but nothing happens and BREAK doesn't work.
So I have to reset the system, and then find the system file is loaded because all commands work properly.
After that everything seems to work as it should.
It looks like some kind of signal timing problem, maybe something with paging of the ROM or WD1772.
Or maybe something with the clock circuit.
I have used 74LS type chips only, so even for the 74LS00 that is used in the clock circuit, and 74LS126 that is used for the DS0, DS1 and SIDE signals on the floppy connector.
Could it be that one of these should be another type, like CMOS?
I will add some leds to visually see which chip is paged, maybe that gives a clue to the problem.
One other thing I'm thinking of is to use UNI-DOS instead of G+DOS, as it's more advanced.
Is there any reason why I shoudn't?
My games for the Spectrum: Dingo, The Speccies, The Speccies 2, Vallation, SQIJ.
Twitter: Sokurah
Booting bug:
- tried 74HCT00 instead of 74LS00 for the clock circuit: no difference
- tried different power supplies and even one 5+12V supply to feed the ZX Spectrum and floppydrive
- tried extra capacitors on the pcb (close to ROM and SRAM) to find out if it's some power glitch
No solution sofar.
My next attempts:
- trying if UNI-DOS makes a difference
- getting a PlusD from a frient to check circuit differences (as the problem also occurs with the PlusD clone from Germany, with GAL)
- adding some paging leds on SRAM, ROM and FDC to find out if there is a paging error or give a clue of what is going wrong, and then maybe get my oscilloscope (an old one) for more detailed analysis
I usually switch on the complete set at once, so the floppy power and ZX Spectrum at the same time.
When I do that, I often have booting issues.
When I power the floppydrives first, and the ZX Spectrum after that, there is no problem....
I'm ashamed. ;)
http://www.youtube.com/watch?v=aB9bz7n0vjQ
When will it be available?
Any special offers, such as a PlusDlite-DualFDD-bundle or an introductory discount? :smile:
schombi.de/my-retro-collection.html"
This weekend I think; working on the 9 left from the first pcb batch.
Oh man, I'm gonna have a shortage on sleep...
Repair Guides. Spanish Hardware site.
WoS - can't download? Info here...
former Meulie Spectrum Archive but no longer available :-(
Spectranet: the TNFS directory thread
! Standby alert !
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb!
Looking forward to summer in Somerset later in the year :)
Anyway, this looks very good. Did you have a chance to think about a case? The +D had its cons, but the massive case was great, I think.
schombi.de/my-retro-collection.html"
Hmmm, I still think cases are a handfull of work.
You must know it already costs a lot of time to do the development of such a new interface, to order parts and to assemble the whole.
If there would be someone who would specialise in building cases for several interfaces...
E.g. Kempston Joystick (I made 3 different versions already: 2012, 2012.2 and 2013), Kempston Mouse Turbo (2005, 2008 and 2011 versions), PC Keyboard Interface (2008 and 2013 upcoming), DivIDE (57C, 2K11), DivMMC, PlusDlite (v1, v1.1), Space Invader Kempston Joystick interface, etc.....
So there is enough work for one person to focus on....
Who is willing to make a living out of this (yeah, that's an invitation from this community)? ;)
Just an idea: when you want to make cases, and deliver one or two of each type to me, I will send you the interfaces for which they are needed.
You can sell the cases separately (mailbox delivery, so cheap) or sell me a ready made batch if there is still some profit left for you.
schombi.de/my-retro-collection.html"
I'd be happy to look into the possibilities of fulfilling an order for case for this or other projects provided order quantity is a bit more than just the odd one or two. I'm sure there'll be some good demand for this though so I doubt numbers will really be an issue in this case.
Feel free to PM me with your requirements