Misc...
Interesting fact: The month of November 1997 recorded ~1000 hits: 33 hits/day
(Howard , 19.12.1996 8:10)
When upgrading an HP48G, could you use higher density chips to
get a larger
memory capacity? In other words, can you use 256K static ram chips
instead
of 128K chips?
See my home page for how to upgrade to more than 256k. It explain how to use port2 of the HP48G, and add 512k for example.
Re: 512k RAM Uprgrade (pka3668@jetson.uh.edu (Poon-Keong (Edward)
Ang), 4.7.1997 16:41)
Newsgroups: comp.sys.hp48
CostaFamily@worldnet.att.net says...
I recently replaced the 32k RAM chip on my HP48G motherboard with
a 512K Static RAM Chip, but when I boot up the calculator and
check the memory, it registers only 128K of RAM. Any suggestions
on this problem would be appreciated.
You will only get 128k because HP48 can only support a max of 128k on each port, ie. port0, port1 etc. By soldering a 512k chip on the same place as the old 32k chip, you are putting 512k on port0. HP48 will only see a max of 128k. The best solution for your case is to buy a 128k chip and replace your 512k chip and use the 512k chip for port2 to port5. You will get 128k of user memory and 128k x 4 of port memory. You can also buy and other 128 chip and solder it on top of the 128k chip, with some of the pins connected to the card slot. This way you can merge port0 and port1 to get 256k of user memory. HP48 will only merge port0 and port1 not any other ports.
(Many people)
Where do we get the SMD Ram chips?
First of all, any kind of static 128k x 8bits ram in SMD package is ok!
Now here's a quotation from the HP48 newsgroup giving some informations
about resellers:
Re: Source for Upgrade RAM in USA? (Elbert Liu , 14.3.1997 3:07)
Newsgroups: comp.sys.hp48
Daniel Wolstenholme wrote:
> Jeffrey R. Kuhn <jkuhn@ccwf.cc.utexas.edu> wrote:
> >Does anyone know of a good source for the surface mount 128K
RAM chips used
> >for the HP48G upgrade here in the USA? Preferably a distributor
that does
> >not have a large minimum order.
>
> Call Mouser Electronics at 800-346-6873. Their chips are $6-8
apiece,
> and there's no minimum order.
That good. Marshall is much better.
1. More selection, NEC, TOSHIBA, SONY and Hitachi any speed, low
power......
2. If you qaulify, you can get samples directly to your door step
FREE!
Otherwise, it's only $4.50 a piece for SONY SRAM CHIPS + UPS shipping.
3. no min either.
Re: 128K Hitachi RAM chips for the HP 48G 32K -> 128K upgrade
(bgarrets@top.eng.utoledo.edu (Blake Garretson), 21.11.1997 6:55)
Newsgroups: comp.sys.hp48
Go to Insight Electronics at http://www.insight-electronics.com and do a product search of hitatchi memory. They have the chips
for $8-$9 and shipping is real low. The whole thing will be less
than $15. It was for me anyway...
Blake
(Darren Berg , 20.11.1996 3:44)
Is there a way to upgrade the HP48GX to 256K internal RAM and
still maintain the functionality of the card slots? Would I be
unable to put cards in slot 1? WOuld I have to leave them unmerged?
Look at the file describing how to upgrade an HP48SX. It has some ideas to install a DIP switch enabling or disabling an upgrade.
Help me with my HP48G ("Andreas Humble" , 27.11.1996 2:41)
5 months ago i bought a hp48g. At first I was impressed (who wouldn`t
be?), but since I discovered games and progs etc on the Internet,
I ran out of memory (32kbyte sucks). Now i want to upgrade to
256k thanks to you. But I have three problems:
Ruining my hp while,
1. opening it.
2. soldering it.
3. putting it together.
I do have experiance in all this (exept with HP), specially soldering
, I even modified my solderingtip. Now....my question. What is
the difficulltylevel in my three problems, between 1 and 10?
1 easiest, 10 very difficult
1) Ok!Openingit isn't a problem if you follow the instructions, and if you
do it carefully! The first time I tried it, I was alone, and it
worked fine!
around level 5
2) soldering:
the first 128k, that's easy! If you have a small soldering iron,
I would rate it at level 4-6
the second 128k, that's painfull... rated at 8... (shortcuts problems)
But don't panic, I had sometimes soldering bridges, and it never
destroyed my HP (at the first time you turn your hp back on, and
the screen stay blank, REMOVE the batteries rapidly!)
3) putting it together
very easy!rated at 2!
Grant Otsuki wrote:
My question is, if I choose to go to 128k, do I need to add the
extra chip, 74HC00 SMD?
You DON'T need the 74HC00 if you have only planned to upgrade
to 128k. On the other hand, you must use it if you want to use
PORT1 memory (used in the 256k memory upgrade).
74HC174? (Ed Kang , 3.12.1997 0:55)
I read your pages, and you only mentioned the installation of
the 74HC00. When do you install the HC174? And what else is the
174 connected to?
The 74HC174 is used to control the bank switching signals of port
2 (and more). It is therefore needed only if you want to do a
"big" upgrade. Until 256k, you don't need it.
A good way to remove HP48g overlay ("Jeffrey R. Kuhn" , 23.2.1997
22:16)
I found a very nice way to remove the overlay. A little 95% ethyl
alcohol works well as a solvent for the glue that holds the overlay
on. It is very volatile, so it dries quickly, and it doesn't hurt
the electronics. I used a syringe and a needle (An eyedropper
might work just as well) to add a little at a time in the groove
surrounding the overlay and to the grooves surrounding each key.
As I worked the overlay loose from the bottom, I added a little
alcohol underneath to loosen the next row. On the side with the
LCD, I just put a little in the groove between the overlay and
the edge of the case and worked the overlay off with a wide, flat
razor-blade. Using this technique, I was able to remove the overlay
with very little bending around the keys, and no bending around
the LCD. It took about 10 minutes to remove the overlay. Rubbing
alcohol (isopropyl alcohol) might work just as well, but I believe
that it is not as volatile as ethyl alcohol.
From my point of view, I would use the isopropyl alcohol, because it usually doesn't attack plastic parts (I don't know very well the effects of ethyl alcohol). Just a question: After this treatment, does the glue still glue, or do you need to add some fresh one?
(einstein@kis.net, 21.11.1996 19:31)
Thanks for the information about upgrading the RAM on the HP48G.
I have had
mine for a while and wanted more RAM but thought that I was just
screwed. I
just finished the upgrade and it works great. Just thought that
I would
tell you how much that I appreciate your efforts. 73 de KF9DJ
Upgrade (Jeffrey Will , 14.10.1997 5:16)
Stephane,
Thank you, thank you, thank you for your wonderful HP48 upgrade
page. It was definitely the best I found. I just got done w/ my
upgrade (this past weekend) and I now have 256K ram on my HP.
I really appreciate the work you put into your page. It is excellent.
I would have had a much more difficult time without it.
Thanks again, and great job.
jeff
last update: January 13th 1998 - Stephane Grundschober