For off-the-shelf stuff that's still available, it's often easiest just to search for the components in question on Mouser or Farnell and download the datasheets from them. Otherwise I generally just use google, which often seems to land me on alldatasheet.com.rubber_jonnie wrote: ↑Sun Apr 25, 2021 9:58 pm Do you know of a good source for datasheets that show all pin connections on the chips?
BBC Model B No2. Will it live again!
Re: BBC Model B No2. Will it live again!
- rubber_jonnie
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Re: BBC Model B No2. Will it live again!
That's where I usually get my datasheets from too, I was just hoping the Beeb schematic would show the power & gnd pins like the ST schematics do, and they do for some, but not for all. The Beeb has a lot of chips and didn't want to look them all up if the schematic showed them.derkom wrote: ↑Mon Apr 26, 2021 5:11 amFor off-the-shelf stuff that's still available, it's often easiest just to search for the components in question on Mouser or Farnell and download the datasheets from them. Otherwise I generally just use google, which often seems to land me on alldatasheet.com.rubber_jonnie wrote: ↑Sun Apr 25, 2021 9:58 pm Do you know of a good source for datasheets that show all pin connections on the chips?
I have now found a troubleshooting book that describes my problem exactly, and goes into more detail, so I will follow that. It's also possible one of the chips is dead as it is supposed to have a heatsink and it's missing. Video chip I think.
I don't think that should stop it booting though.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
- stephen_usher
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Re: BBC Model B No2. Will it live again!
The chip with(out) the heatsink is the ULA. The original Ferrari ones ran hot and die if the heatsink is missing.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
Re: BBC Model B No2. Will it live again!
Even with the heatsink, mine ran very hot & all the blacks would start to turn into a noisy red pattern...with the newer video ULA it ran fine for hours with no obvious issuesstephen_usher wrote: ↑Mon Apr 26, 2021 9:28 am The chip with(out) the heatsink is the ULA. The original Ferrari ones ran hot and die if the heatsink is missing.
Re: BBC Model B No2. Will it live again!
The ULA generates all the clocks for the model B. If it is dead you will get nothing.rubber_jonnie wrote: ↑Mon Apr 26, 2021 9:22 am I have now found a troubleshooting book that describes my problem exactly, and goes into more detail, so I will follow that. It's also possible one of the chips is dead as it is supposed to have a heatsink and it's missing. Video chip I think.
I don't think that should stop it booting though.
- rubber_jonnie
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Re: BBC Model B No2. Will it live again!
This is the frustration, I want to check the clocks, but my oscilloscope is in storagecmorley wrote: ↑Mon Apr 26, 2021 9:35 amThe ULA generates all the clocks for the model B. If it is dead you will get nothing.rubber_jonnie wrote: ↑Mon Apr 26, 2021 9:22 am I have now found a troubleshooting book that describes my problem exactly, and goes into more detail, so I will follow that. It's also possible one of the chips is dead as it is supposed to have a heatsink and it's missing. Video chip I think.
I don't think that should stop it booting though.
Looking at the ULA, it doesn't appear to have ever had a heatsink on it. No glue residue, nothing. Plus it had a green QC sticker on it, though that's since fallen off!! The one that I'm referring to is IC6, which according to the schematic is the video processor, and that shows no signs of a heatsink ever being attached to it.
It's an issue 4, and of the photos I can find, some have a heatsink on IC6, some don't. None of the issue 7 board photos I can find show a heatsink on IC6, so it is feasible that IC6 was replaced with a later version that doesn't need a heatsink. If I'm honest, it looks newer than the rest, and no signs of any gunge that would have held a heatsink on.
I think I'll have to pull the ULA, clean the pins up and check for power too, and I'll follow the troubleshooting guide which suggests my symptoms point at a problem with IC36.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: BBC Model B No2. Will it live again!
The original Ferranti ones need a heatsink. The later VIA ULAs do not.
- rubber_jonnie
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Re: BBC Model B No2. Will it live again!
ULA is Ferranti, so wondering why no evidence of a heatsink..... If that is dead then all bets are off for now. Really wish I had my other Beeb here.
IC6, the video processor is a VIA.
I really ought to do some work I suppose!! But this is more interesting!
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: BBC Model B No2. Will it live again!
The serial/cassette ULA (SERPROC IC7) never had heatsink & never needed one. Only the Ferranti made main ULA (VIDPROC IC6).
- rubber_jonnie
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Re: BBC Model B No2. Will it live again!
Ahh, right, I think I was misunderstanding on account of being used to Sinclair machines with a single ULA.
So two ULAs then, and my VIDPROC IC6 is a VIA ULA so that's a good start, I'm getting to know the geography of the board a bit better.
Are there any other ULAs I should know about?
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...