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cjmcc · 10-29-2019, 12:38 PM

My son's calculator has decided to go on strike just before a major exam. The display shows pixels in a horizontal line, but won't respond. He changed the batteries. He tried a soft reset (asked about trying to recover memory, but nothing after that). Tried a paperclip into the back reset slot. Any suggestions for this poor device.

(Right now, I'm express mailing him MY HP50G for his exam.)

Claudio L. · 10-29-2019, 01:40 PM

(10-29-2019 12:38 PM)cjmcc Wrote: My son's calculator has decided to go on strike just before a major exam. The display shows pixels in a horizontal line, but won't respond. He changed the batteries. He tried a soft reset (asked about trying to recover memory, but nothing after that). Tried a paperclip into the back reset slot. Any suggestions for this poor device.

(Right now, I'm express mailing him MY HP50G for his exam.)

If he can get to the "Try to recover the memory" message the device is still alive and booting. I believe the cause might've been perhaps a bad crash started writing to the Flash in all the wrong places, now the ROM is corrupted and cannot start.
My suggestion is to do this:
Holding + and - simultaneously, use the paperclip to access the boot loader. Then flash the 2MB_FIX rom file that's on hpcalc.org . This is a special ROM that will erase and rewrite the entire flash chip. Any blocks that might've been compromised will be repaired.
You WILL lose all data and all libraries installed in flash as well, but will likely get you back the calculator in perfect condition.

cjmcc · 10-29-2019, 03:19 PM

(10-29-2019 01:40 PM)Claudio L. Wrote:
(10-29-2019 12:38 PM)cjmcc Wrote: My son's calculator has decided to go on strike just before a major exam. The display shows pixels in a horizontal line, but won't respond. He changed the batteries. He tried a soft reset (asked about trying to recover memory, but nothing after that). Tried a paperclip into the back reset slot. Any suggestions for this poor device.

(Right now, I'm express mailing him MY HP50G for his exam.)

If he can get to the "Try to recover the memory" message the device is still alive and booting. I believe the cause might've been perhaps a bad crash started writing to the Flash in all the wrong places, now the ROM is corrupted and cannot start.
My suggestion is to do this:
Holding + and - simultaneously, use the paperclip to access the boot loader. Then flash the 2MB_FIX rom file that's on hpcalc.org . This is a special ROM that will erase and rewrite the entire flash chip. Any blocks that might've been compromised will be repaired.
You WILL lose all data and all libraries installed in flash as well, but will likely get you back the calculator in perfect condition.

Thank you for the reply. I'll get my hands on the misbehaving calculator at Thanksgiving and give this recovery routine a try.

BTW - College kids these days are very Amazon conditioned. Need something desperately, and Amazon Prime will take care of you. Has anyone seen the going prices for an HP49G+? Amazon lists a new one for $229.99 and a dodgy used one for $69.99 (plus $49.99 shipping!!!!).

grsbanks · 10-29-2019, 06:56 PM

(10-29-2019 03:19 PM)cjmcc Wrote: BTW - College kids these days are very Amazon conditioned. Need something desperately, and Amazon Prime will take care of you. Has anyone seen the going prices for an HP49G+? Amazon lists a new one for $229.99 and a dodgy used one for $69.99 (plus $49.99 shipping!!!!).

You're better off not even looking for a 49G+. Those manufactured for most of the calculator's lifespan had poor quality keyboards that introduced errors in your input (missed keystrokes our bounce) or even broke physically. You're much better off looking for a 50g anyway because the keyboard problem was solved by the time it came out and because the black body and light-coloured markings make for a much more readable machine (better contrast in the colour scheme).

There are numerous 50g units -- second hand, admittedly -- available on eBay at prices far, far below those ludicrous prices for 49G+ units.

Basically, the only differences between the 49G+ and the 50g are the serial port (nobody actually uses it!) and the fact that you can power the 50g over the USB connection. Other than that, it behaves exactly like the 49G+.

cjmcc · 10-31-2019, 11:45 AM

(10-29-2019 12:38 PM)cjmcc Wrote: My son's calculator has decided to go on strike just before a major exam. The display shows pixels in a horizontal line, but won't respond. He changed the batteries. He tried a soft reset (asked about trying to recover memory, but nothing after that). Tried a paperclip into the back reset slot. Any suggestions for this poor device.

(Right now, I'm express mailing him MY HP50G for his exam.)

Two hours after I spend $29 for Priority Mail Express, my son calls to tell me he tried a fresh set of batteries and his calculator is working. The good news is I don't have to try and fix his calculator over Thanksgiving.

pinkman · 10-31-2019, 01:10 PM

What model did you finally buy, and for what price?
Remember there is a classified forum to sale your new calculator.

cjmcc · 10-31-2019, 08:11 PM

(10-31-2019 01:10 PM)pinkman Wrote: What model did you finally buy, and for what price?
Remember there is a classified forum to sale your new calculator.

The $29 only covered my donation to the US Postal Service. The calculator mailed was MY HP50g. (That only leaves me with an HP29C, an HP15C, an HP33S, and an HP35s to handle my calculating needs.)

For an economical replacement, prowling the on-line auctions for an HP50g or a late-model HP49g+ seem to be the best option. But I am intrigued about getting my hands on a HP39g for less than $25 and trying to install NewRPL.