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L2 cache missing on 486

oblivion

oblivion

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I recently have been toying with an old Packard bell 486. it seems to be missing any l2 cache chips on the mb. i confirmed that visually and by using cache check. the machine was previously unopened so apparently this is how it was sold. there are sockets for chips and the MB diagram on the case states they are indeed cache sockets.

my question is what kind of chips am I looking for exactly? the MB is Packard bell proprietary so there's not really much info on it available. the sticker does have jumper positions for 32 - 512k chips.
 
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its a PB legend 115. nice little compact 486 but its giving me all sorts of issues other then cache. tried installing a cd-rom drive but I'm not sure it even supports it in BIOS as when I load DOS I just get "CD DRIVE MISSING"
 
I think you mean 32 pins (16 per side). So 4 for cache and 1 for tag. Given the date, could be 32Kx8 or 64Kx8, probably 20 (tag)-25 nsec. cache.

Unless you've got access to a lot of these chips, they can be very expensive.

See this for some info on the PB400-series boards, which probably match up with your board. Note the same 28/32 pin "combo" sockets.
 
That looks to be the same motherboard that's in my Packard Bell "Multi-Media".

Mine has 256KB cache onboard directly, as well as the cache slots. I'll be able to tell you for sure tomorrow, however I would check the BIOS for any settings. Mine has the same overdrive socket as well as a 33 MHz 486 SX, 4 megs ram onboard and a 140 or so meg hard drive.

Mine also shipped with a CD-ROM, however it's a Panasonic CR-563 on an Aztec sound card rather than IDE.
 
Packard Bell models are NOT taken by the name on their front. The rear model (EG: A940-TWR) is the proper one.

It's also not unknown that really cheap or really shady computer dealers and shops (Packard Bell falls into this class) to skimp out on cache memory because even back then it was extremely expensive.
 
Compgeke said:
That looks to be the same motherboard that's in my Packard Bell "Multi-Media".

Mine has 256KB cache onboard directly, as well as the cache slots. I'll be able to tell you for sure tomorrow, however I would check the BIOS for any settings. Mine has the same overdrive socket as well as a 33 MHz 486 SX, 4 megs ram onboard and a 140 or so meg hard drive.

Mine also shipped with a CD-ROM, however it's a Panasonic CR-563 on an Aztec sound card rather than IDE.
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sounds like the same specs as mine almost. except mine had no cd-rom drive and I cant seem to be able to install one via the onboard IDE. I've bumpred my RAM to 20mb, threw in an old conner 420MB hard drive and replaced the 25SX with a 33DX.

i'm hoping finding the cache though doesn't make it more trouble then its worth. I have an old PB with a Pentium 75 in it. maybe pull that out and check if it uses the same type later. one nice things is I can disable the on board I/O with a jumper so maybe i'll pick up an ISA IDE controller, may give me better results with newer hard drives and CD drives.

model on back is PB411A
 
It is a bit difficult, but I count either 13 or 15 pins in the sockets. No standard RAM chips ever had that number, either 24 or 28 so 12 or 14 per side. What are the surface mount chips on the MB under the SIMM? Four of, could be cache because close to the 486.

I still have fast 32Kx8 SRAMs from when they were bought for a product I was developing, probably -25, -35 or -45, have to find them to look.
 
woodchips said:
It is a bit difficult, but I count either 13 or 15 pins in the sockets. No standard RAM chips ever had that number, either 24 or 28 so 12 or 14 per side. What are the surface mount chips on the MB under the SIMM? Four of, could be cache because close to the 486.

I still have fast 32Kx8 SRAMs from when they were bought for a product I was developing, probably -25, -35 or -45, have to find them to look.
Click to expand...

You must be trying to count the pins by looking at a cell phone screen. :) Click on the photo and zoom if necessary.

There are three rows of pins for each socket--2 rows of 16 and one row of 14. This appears to allow 0.400" wide 32-pin cache SRAMs or 0.300" wide 28-pin cache SRAMs. Nothing unusual about them.
 
woodchips said:
It is a bit difficult, but I count either 13 or 15 pins in the sockets. No standard RAM chips ever had that number, either 24 or 28 so 12 or 14 per side. What are the surface mount chips on the MB under the SIMM? Four of, could be cache because close to the 486.

I still have fast 32Kx8 SRAMs from when they were bought for a product I was developing, probably -25, -35 or -45, have to find them to look.
Click to expand...

not sure what the chips under the simm are. Mb diagram on inside of the case says those empty sockets are l2 cache. Cache check program also confirms no l2 mem.
 
You mean 5x32-pin chips or 5x28 pin chips.

I think that the 28 pin guys will be easier to find and cheaper. Of course, that's less cache. Note that the tag RAM chip must be at least 20 nsec. speed. Anything slower will give you problems.
 
Chuck(G) said:
You mean 5x32-pin chips or 5x28 pin chips.

I think that the 28 pin guys will be easier to find and cheaper. Of course, that's less cache. Note that the tag RAM chip must be at least 20 nsec. speed. Anything slower will give you problems.
Click to expand...

thanks chuck, i'm a newbie when it comes to cache. is Tag RAM a completely different kind of chip or can it be the same as other 4?
 
oblivion said:
not sure what the chips under the simm are.
Click to expand...
You may well find the system has a small amount of ram on the mobo, say 4megs seem, as the system is showing 20megs total. So 4meg on board and one 16meg stick.

It should'nt be too difficult to get the cdrom up and running. Sounds like the dos cd divers or cd/hdd jumper may not be correctly set up. Also Conner drives can be picky with what they play nice with.
 
Caluser2000 said:
You may well find the system has a small amount of ram on the mobo, say 4megs seem, as the system is showing 20megs total. So 4meg on board and one 16meg stick.

It should'nt be too difficult to get the cdrom up and running. Sounds like the dos cd divers or cd/hdd jumper may not be correctly set up. Also Conner drives can be picky with what they play nice with.
Click to expand...

there is indeed 4MB on the motherboard but I don't believe that is L2 cache. I think its just standard RAM....unless there's really no difference. I was under the impression that RAM used for cache and your standard SIMM/DIMMS for system RAM were different.
 
oblivion said:
there is indeed 4MB on the motherboard but I don't believe that is L2 cache. I think its just standard RAM....unless there's really no difference. I was under the impression that RAM used for cache and your standard SIMM/DIMMS for system RAM were different.
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It is different and your L2 cache definately not there ;) As those chips where under the stick and you mention you had 20megs of ram onboard all up it was a pretty safe bet they where just "normal" ram chips laying there. It wasn't uncommon for a number of OEMs to do this.
 
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