Fix Spice with unsoldered chips?



#11

I've a once-working 31E with unsoldered chips. I'd like to make it my desktop device -- just 'cause it's got RRREEEDDD LLLEEEDDDs! (Who was/is it that got known for gushing over LEDs so profusely?)

It needs a power pack too, and both clips are broken off of the little battery/recharger connector PCB, and a nearby piece of the back case is missing. Unfortunately, it exhibits the infamous "2 disease", which I attribute to having used alkaline cells rather than Ni-Cds. (I think forcing alkalines into a Spice can lead to - or exacerbate - lots of problems!)

I assume my approach should be: solder the chips to the circuit board and connect some sort of two-cell power pack? (Maybe a cordless phone pack with two Ni-Cds?) I'd rather have it portable, than rechargeable, if I'm faced with that as a trade-off.

Any further advice or options?

Thanks.


#12

Quote:
Unfortunately, it exhibits the infamous "2 disease"

What exactly do you mean?


#13

I can only vaguely remember, as I haven't used this calc for years. But there's been some discussion of this elsewhere -- you may wish to do a little searching.

IIRC, when actually pressing digits (any keys?), the display briefly flashes with "22222222..." all the way across. I don't think there's any other manifestation, and when the key is released, the display goes back to normal.

There has been some discussion re: the cause. It did seem to me, way back when I was paying attention, that the only common thread appeared to be that afflicted calculators (all Spice models) had at least once been run on disposable (alkaline) batteries.

Someone will surely correct me if I'm off base.

I did find this - older - discussion. Apparently, the problem only occurs when there's one or more "2" in the display -- then "ghost" 2's start showing up with keypresses.


Edited: 4 Jan 2010, 6:22 p.m. after one or more responses were posted


#14

I have a dozen working Spices, and I've never seen this phenomenon on any of them.


#15

I'm curious -- have you ever run any of them on disposable AA batteries (rather than NiCd rechargeables)?

Thanks


#16

No. However, many of them were probably used this way by their previous owners, since the battery contacts were either bent or broken due to the use of high-top AA cells. I only use flat-top AA NiCads.

#17

Hi, Paul;

the "2 disease" term was first used by Norm (AKA Captain Zener) after seeing many 2´s being randomly shown in the display of some Spices while performing a few regular operations, mostly while running programs. Same models with same internals might have or not the so called '2´s disease', different models with different internals might also have it or not. No pattern was established or observed at that time. In one particular case, IIRC, one calculator without the '2´s disease' came up with it after being serviced. I do not recall the actual circumstances, but it seems to me that something wrong happened and the '2´s disease' was then classified as a hardware flaw.

Norm firmly believed it was a design flaw, and I disagreed with him by defending it as a design characteristic, instead. We never got to a consensus, and I believe that only the guys who designed the firmware have the answer.

As all calculators ended up operating accordingly, no further mentioning was made till now.

That´s all I can tell without 'digging' the archives.

Cheers.

Luiz (Brazil)

Edited: 4 Jan 2010, 5:36 p.m.


#18

Ahh, yes. And it was that same Norm (or, "Captain Zener") who had the hilarious habit of waxing poetic about RED LEDs!

Hello out there, Norm -- wherever you are!

#19

Solder the chips and the LED array into place. I normally clean the leads of the IC's first as they will be oxidized and not want to solder well at all which is why they don't like to work with pressure alone.

If you want a charger and battery, shoot me an email, I can fix you up...


#20

Use a decent (temp controlled) soldering iron and remember that the chips are very very sensitive to static so use an antistatic mat and wrist strap. I killed my original HP33C trying to repair it - took me 18 years to get another!

Mike T.


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