Wanted: A5000 Alpha FPA Chip

wanted ads for hardware, software + literature (NOT for tape/disc image requests)
Forum rules
You're welcome to trade Acorn-related stuff with other forum members here - the rule of thumb to follow when trading, is that items or services offered should be of interest to our Acorn community. Do NOT use multiple accounts - please trade with your regular (and only) forum account. If you're giving items away, please make it clear if you would be unhappy with the recipient selling on some or all of the items. Similarly, please ensure that the giver is comfortable with you re-selling items you have accepted as a gift. We cannot be held responsible for what happens in these trading forums or for deals done via PM. This must be done at your own risk. If you aren't comfortable with this - make the trade via an alternative site which can apply safeguards of their own. Be sensible - if someone approaches you to trade via PM who is not posting in the public forums, this may be a sign that they are not entirely what they seem. Please report it to the moderators if you receive an unsolicited message from anyone suspicious, so that it can be investigated and hopefully stop anyone being taken advantage of.
Post Reply
User avatar
nOmArch
Posts: 1330
Joined: Fri May 21, 2010 7:27 pm
Location: Gloucestershire
Contact:

Wanted: A5000 Alpha FPA Chip

Post by nOmArch » Thu Apr 05, 2012 5:00 pm

CJE have them for £50 just wondering if anyone has one they want to get rid of for a sensible price or is there a modern day equivalent I could drop in?
Alex

Back up to 1 Beeb again. \o/

User avatar
paulv
Posts: 3631
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by paulv » Thu Apr 05, 2012 5:07 pm

They're rocking horse poo! Hence the CJE price!

Also, if you look very carefully at that FPA socket of yours, there's a green tinge to some of the pins due to the battery leakage so it may be hit an miss on the working front. Before you go spending on the chip, I'd continuity check the socket or look at getting it replaced.

Paul

User avatar
SarahWalker
Posts: 1098
Joined: Fri Jan 14, 2005 3:56 pm
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by SarahWalker » Thu Apr 05, 2012 5:39 pm

I don't think there is one suitable for the A5000 Alpha. The one CJE has is only rated for 25MHz, not 33. While there is a (very rare!) FPA11 suitable for 33MHz, the A5000 power supply is apparently too noisy for it to work properly.

User avatar
nOmArch
Posts: 1330
Joined: Fri May 21, 2010 7:27 pm
Location: Gloucestershire
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by nOmArch » Thu Apr 05, 2012 6:27 pm

Ahhh didn't realise this was another hens teeth situation, thanks for the heads up guys.
Alex

Back up to 1 Beeb again. \o/

AndyMc1280
Posts: 591
Joined: Sat Aug 27, 2011 10:50 am
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by AndyMc1280 » Mon Apr 09, 2012 3:16 pm

FPA 10 s will work in an Alpha. Bung a heatsink on if you are worried and bob is your auntie's husband. My mates got one and its fine.

http://grope.thruhere.net/Qube/systems/A3000ARM3.html

Charlie has one in his A3000 and has overclocked it to 33 Mhz. If you put one in standard it will run at 25 Mhz.

http://acorn.chriswhy.co.uk/Computers/A540.html

Chris Whytehead's got one running in an A540 with the CPU at 33 Mhz and the FPA10 at 26.... (look at the tables)

I have a R260 without an FPA10 CPU card, I plan on eventually getting an FPA10 somehow.

So, you should be fine running it at stock speed, even in a 33Mhz system.

User avatar
nOmArch
Posts: 1330
Joined: Fri May 21, 2010 7:27 pm
Location: Gloucestershire
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by nOmArch » Mon Apr 09, 2012 3:34 pm

Ahh that's certainly good news, looks like CJE is gonna get more of my cash then :evil: lol
Alex

Back up to 1 Beeb again. \o/

User avatar
SarahWalker
Posts: 1098
Joined: Fri Jan 14, 2005 3:56 pm
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by SarahWalker » Mon Apr 09, 2012 8:17 pm

I think it should be emphasized at this point, that almost nothing uses the FPA - it was so rare that floating point instructions on Arc software was avoided like the plague. It's certainly far from an essential upgrade.

Of course if you were already aware of this then disregard this post!

User avatar
nOmArch
Posts: 1330
Joined: Fri May 21, 2010 7:27 pm
Location: Gloucestershire
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by nOmArch » Mon Apr 09, 2012 9:56 pm

Ahhh good to know! I just want to make it the best it can be, if it doesn't actually make any difference then I can save my money and get something more useful.
Alex

Back up to 1 Beeb again. \o/

poink
Posts: 963
Joined: Tue Mar 01, 2011 10:27 am
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by poink » Sat Jun 02, 2012 1:41 am

TomWalker wrote:I think it should be emphasized at this point, that almost nothing uses the FPA - it was so rare that floating point instructions on Arc software was avoided like the plague. It's certainly far from an essential upgrade.
I'd been wondering the same regarding my own A5000 Alpha, I'd come to the conclusion that it really wasn't worth fitting one, so it's nice to have confirmation of that reasoning.

I suspect that floating point would have got some support if it had been available on more than just ARM3+FPA10 and the 7500FE. Worse, memory suggests that FPEmulator didn't exactly have a reputation for being fast either!

I really wish I'd had an A5000 Alpha back in the day - it goes like a greased whippet!

User avatar
davidb
Posts: 2155
Joined: Sun Nov 11, 2007 10:11 pm
Contact:

Re: Wanted: A5000 Alpha FPA Chip

Post by davidb » Sat Jun 02, 2012 3:30 pm

I have vague memories that my A7000+ performed as well as a StrongARM RiscPC on some benchmarks precisely because they were so floating point intensive. It's a real shame that the SA-1500 never made it into a product.

Post Reply