HP-41CV power problem - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: HP-41CV power problem (/thread-232703.html) |
HP-41CV power problem - Don Davis - 10-10-2012 I have an HP-41CV exhibiting a strange problem. First, it is difficult to turn on. The on key must be depressed several times, perhaps even holding it down for a few seconds. I suspected this was simply a contact problem - however, once it is on, it powers off by itself after about 10 seconds. New batteries, memory clear, and no flags set. Any advice is appreciated. The power button problem has been there for a while, but the auto-power-down problem just came up.
Thanks, Re: HP-41CV power problem - Bruce Larrabee - 10-10-2012 There is a capacitor on the mother board that can cause this problem. The capacitor is designated C2 and the long and short of it is that if your display driver assembly is covered in epoxy the you use a 470 pf cap and if it is covered with a plastic cover you use a 0.01 uf cap. Check that you have the right cap and that it is good. The following is from the service manual.
There are differences in appearance as well as in the automatic Revision "G" uses 470 pf/D160-057l Revision "F" uses .01 uf/0160-3914
The difference in appearance can be seen by looking at the covering Revision "G" is covered by epoxy . Revision "Fit is covered by a plastic cap . If the value of capacitor is interchanged with revi sion of the display driver assembly the following symptoms occur: 1. Revision "Gil with 470 pf Frequency = 8.3 KHZ Timeout = 9 mi nutes Display = OK 2. Revision "G" with . 01 uf Frequency = 435 KHZ Timeout - , • Display = fli ckering 3. Revision "F" with . 01 uf Frequency = 6.3 KHZ Timeout - 12 minutes Di spl ay = OK 4. Revision "F" with 470 pf Frequency - 110 KHZ Timeout - 40 seconds
Display - OK
Re: HP-41CV power problem - Don Davis - 10-11-2012 Bruce,
Best regards, |