Power supply for HP Spice series (european)

[pascal_meheut]

Hi,
I'm daily using a HP-32e but the power supply failed (as well as my backup). They are becoming hard to find so I was wondering if there is any way to repair them or an alternative such as a way to charge the battery outside the calculator?

Help!!!

[Geoff Quickfall]

Hello Pascal

I assume you have a sealed two battery NiCad pack. You might consider changing to two single NiCads and purchasing an external NiCad battery charger. The caution is, don't force them into the battery holder. Newer batteries are a silly mm longer then the design called for, so shop around for the shortest ones in the market.

Others purchase a AAA dual battery holder, again shop around for one that fits, then they insert either rechargeable AAA or alkaline AAA. This if the battery tabs have been broken or fatigued.

Although the spice and others do not suffer the Woodstock power design fault I would suggest with the alternatives out there that there is NO need to stress 40 year old components in a vintage calculator for the sake of convenience! Yes I know, others will say; " I have never had a problem as long as you monitor your battery condition" but why risk it.

Geoff

[Dieter]

(07-17-2015 01:41 PM)pascal_meheut Wrote:  I'm daily using a HP-32e but the power supply failed (as well as my backup). They are becoming hard to find so I was wondering if there is any way to repair them or an alternative such as a way to charge the battery outside the calculator?

My 34C runs on two standard Sanyo (now Panasonic) Eneloop NiMHs with a nominal capacity of 2000 mAh. Which means about four times the original battery's capacity. The two standard AA cells fit nicely into the battery compartement and they are connected with a piece of folded aluminium foil. I think there was some kind of metal clip at the right hand side of the battery compartment, which now is missing. Maybe this gives the additional millimeter of space that's required for the two batteries. On the other hand you may also consider special flat top cells. These are slightly shorter than their regular counterparts.

Charging is done externally with a decent processor controlled charger, usually within three or four hours. Which is not required very often since the capacity is so much higher than it used to be. Also, the Eneloops have virtually no self-discharge, i.e. they do not lose (much) capacity if the calculator is not in use.

Works for me.

BTW, since you own a 32E: could you do me a favour?
How long does does the Q^–1 function require for x=1E–99, 0,01 and 0,2 ? That's something I always wanted to know. ;-)

Dieter

[Geoff Quickfall]

Dieter wrote:


"I think there was some kind of metal clip at the right hand side of the battery compartment, which now is missing. Maybe this gives the additional millimeter of space that's required for the two batteries. On the other hand you may also consider special flat top cells. These are slightly shorter than their regular counterparts."

In fact, the calculator came with a metal bracket which included the connection for the batteries opposite to the contacts, negating the requirement for the foil. There was no connection physically attached to the calculator opposite the contacts as the battery clip contained it.

The bracket made of metal increased the length of the battery and with new alkalines causes stress on the battery tabs. The foil works perfectly and your suggestion of the flat tops cells, if available is perfect.

Geoff

[pascal_meheut]

(07-17-2015 07:16 PM)Dieter Wrote:  How long does does the Q^–1 function require for x=1E–99, 0,01 and 0,2 ?

According to the WP34s stopwatch:
1E-99 : 12.9 sec
0.01 : 12.5 sec
0.2 : 7.5 sec

[pascal_meheut]

(07-17-2015 05:16 PM)Geoff Quickfall Wrote:  I assume you have a sealed two battery NiCad pack. You might consider changing to two single NiCads and purchasing an external NiCad battery charger. The caution is, don't force them into the battery holder. Newer batteries are a silly mm longer then the design called for, so shop around for the shortest ones in the market.

Others purchase a AAA dual battery holder, again shop around for one that fits, then they insert either rechargeable AAA or alkaline AAA. This if the battery tabs have been broken or fatigued.

Thanks. I was also considering find a 220 V AC -> 9V AC converter and connecting one of my faulty hp-82090b cable to it. Did anybody tried this?

[Geoff Quickfall]

Someone correct me please, but I think you want a DC output, not 9v AC.

Also, I haven't got one in my hand but the power supply is fixable. Is not held together by screws? Also the cap inside usually is the suspect, oil filled and subject to heat plus 30 years old. Have you tried taking it apart?

[Dieter]

(07-18-2015 05:45 AM)Geoff Quickfall Wrote:  Someone correct me please, but I think you want a DC output, not 9v AC.

This source says the 82090B contains just a simple transformer that delivers 9 V AC. Nominally, that is.

However, I'd be very careful with a different AC adapter, even if it has the same nominal rating. Maybe someone can measure the 82090B's open circuit voltage as well as the effective output voltage while the batteries are charged. Maybe even someone can provide the charging current.

Dieter

[Katie Wasserman]

(07-18-2015 05:45 AM)Geoff Quickfall Wrote:  Someone correct me please, but I think you want a DC output, not 9v AC.

Consider yourself corrected! It's 10v AC (mine says 10V not 9V, but it's not regulated anyway).

Quote:Also, I haven't got one in my hand but the power supply is fixable. Is not held together by screws? Also the cap inside usually is the suspect, oil filled and subject to heat plus 30 years old. Have you tried taking it apart?

No screws on mine (120V model) there's just a transformer in there.

[Dieter]

(07-18-2015 05:18 AM)pascal_meheut Wrote:  

(07-17-2015 07:16 PM)Dieter Wrote:  How long does does the Q^–1 function require for x=1E–99, 0,01 and 0,2 ?

According to the WP34s stopwatch:
1E-99 : 12.9 sec
0.01 : 12.5 sec
0.2 : 7.5 sec

Whoa... thank you. That seems to be quite a task for this little device. ;-)

I recently designed two rational approximations for the Normal quantile function, optimized for the range down to 1E–100 and ~ 11 digit accuracy. Implemented in a 35s user program, the results are returned in about 1...2 seconds.

Dieter

[Geoff Quickfall]

This falls under the category of "just ask Katie".

Away from home so I couldn't check mine physically.

Thanks Katie!