Picasso II Burned Resistor - Page 2

SpeedGeek · 19 January 2011, 16:51

Your analysis is correct except that the Zorro 2 state machine always adds at least one wait state to every cycle even if no other boards are present. The sloppy cycle bus snooping logic may delay the start of a Zorro 3 cycle when a Zorro 2 board shares the bus with a Zorro 3 board but thats not the cause of the slower Zorro 2 cycles. Its really a case of sloppy state machine design.

Basically my mod speeds up SuperBuster by switching the 7 Mhz clock to a 14 Mhz clock durring the 2nd part or data buffer enable portion of a Zorro2 cycle. I suppose everyone will want a schematic and detailed instructions on how to do this.

chiark · 19 January 2011, 19:54

That sounds like a neat hack! Does it not need to keep 7MHz clock for compatibility's sake on the data transfer?

SpeedGeek · 20 January 2011, 05:19

Your question was answered in the "SuperBuster Zorro2 Speedup Mod" thread.

kamelito · 12 March 2011, 16:54

Same problem here but only the Resistor has burnt the board is intact.
I will remove It as soon as I get my hand on my soldering iron.

Thanks
Kamel

18 September 2013, 15:29

hi guys, many thanks to everybody who sorted out the burnt resistor problem.
Its been a great help and I've managed to recover my Picasso II after 25 years in the attic!!

spudje · 01 April 2015, 10:29

Sorry to revive this thread. But I just wanted to be sure whether or not I risk similar resister blow outs on a Phase 5 CyberVision 64 (not 3D)? I saw one LCD monitor in this thread that works with the card, but that may just be a lucky combination. Or is the design different for the CyberVision 64, i.e. no voltage on pin 9?

Jope · 01 April 2015, 11:53

No need to worry.

pneron · 01 April 2019, 12:54

hmmmm, to be clear, are you suggesting NOT to replace the resistor? Looks like my Diode, Resistor and Relay are blown. The card does work but I do get occasional boot-up graphic problems which require multiple tries before getting into Picasso II (ver 1.6) mode?

oggie · 11 April 2021, 00:30

Should you remove the same resistor for the other connector, or is this resistor only used on the one output?

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19 January 2011, 16:51	#21
SpeedGeek Moderator Join Date: Dec 2010 Location: Wisconsin USA Age: 60 Posts: 841	Your analysis is correct except that the Zorro 2 state machine always adds at least one wait state to every cycle even if no other boards are present. The sloppy cycle bus snooping logic may delay the start of a Zorro 3 cycle when a Zorro 2 board shares the bus with a Zorro 3 board but thats not the cause of the slower Zorro 2 cycles. Its really a case of sloppy state machine design. Basically my mod speeds up SuperBuster by switching the 7 Mhz clock to a 14 Mhz clock durring the 2nd part or data buffer enable portion of a Zorro2 cycle. I suppose everyone will want a schematic and detailed instructions on how to do this.

19 January 2011, 19:54	#22
chiark Needs a life Join Date: Jan 2008 Location: England Posts: 1,707	That sounds like a neat hack! Does it not need to keep 7MHz clock for compatibility's sake on the data transfer?

20 January 2011, 05:19	#23
SpeedGeek Moderator Join Date: Dec 2010 Location: Wisconsin USA Age: 60 Posts: 841	Your question was answered in the "SuperBuster Zorro2 Speedup Mod" thread.

12 March 2011, 16:54	#24
kamelito Zone Friend Join Date: May 2006 Location: France Posts: 1,801	Same problem here but only the Resistor has burnt the board is intact. I will remove It as soon as I get my hand on my soldering iron. Thanks Kamel

18 September 2013, 15:29	#25
BREAMTECH Posts: n/a	hi guys, many thanks to everybody who sorted out the burnt resistor problem. Its been a great help and I've managed to recover my Picasso II after 25 years in the attic!!

01 April 2015, 10:29	#26
spudje Registered User Join Date: Dec 2014 Location: Netherlands Posts: 1,406	Sorry to revive this thread. But I just wanted to be sure whether or not I risk similar resister blow outs on a Phase 5 CyberVision 64 (not 3D)? I saw one LCD monitor in this thread that works with the card, but that may just be a lucky combination. Or is the design different for the CyberVision 64, i.e. no voltage on pin 9?

01 April 2015, 11:53	#27
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,864	No need to worry.

01 April 2019, 12:54	#28
pneron Registered User Join Date: Feb 2018 Location: Boston MA Posts: 20	hmmmm, to be clear, are you suggesting NOT to replace the resistor? Looks like my Diode, Resistor and Relay are blown. The card does work but I do get occasional boot-up graphic problems which require multiple tries before getting into Picasso II (ver 1.6) mode?

11 April 2021, 00:30	#29
oggie Registered User Join Date: Apr 2017 Location: Quispamsis Posts: 89	Should you remove the same resistor for the other connector, or is this resistor only used on the one output?

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