▼
Posts: 229
Threads: 67
Joined: Jul 2007
A friend of mine gave me his old dead HP42S that he had stored away. I removed the batteries and replaced them with brand new ones. It came on for one brief milisecond.
It displayed 'memory lost' and then went dead again.
I played with it until it came on enough to perform the self test, which it passed.
Then it went dead again. And nothing I did brought it back.
Not even a severe banging up.
I sprayed it until it was drenched with [you would not believe] WD40.
I put it to dry for a few hours.
Then last night I replaced the batteries and....Guess what?
It works. It passes the self test and remains working up till now.
I even programmed it with some simple programs and the calc. retains everything.
Is this a miracle cure? Or could someone offer an explanation?
Thanks,
Iqbal
▼
Posts: 298
Threads: 35
Joined: Jan 1970
Did the internal capacitor finaly discharge when you left it alone to dry out?
Did you short out the battery terminals at any point?
Posts: 1,162
Threads: 26
Joined: Aug 2005
I am not sure whether to laugh or cry... I generally refer to WD40 as 'Wanton Destruction 40' because of the mess it makes of fine machinery and electronics.
In general repairing sometnhing that has sprayed with WD40 takes about 3 times as long as just fixing it properly because the device has to be totally dismantled, cleaned and reassembled. Wd40 leaves a waxy deposit behind that will gum up mechanical parts, prevent swtich contacts from making properly, and so on.
If you must spray anything into a calculator, use something like pure propan-2-ol (isopropanol) that will not leave a residue behind.
Most likely the problem with the HP42S, if the WD40 did anything (and it wasn't just leaving the batteries out that cured it) was a small electrical leakage
between connections inside. WD40 might have shifted that, (as might propan-2-ol), but wouldn't be suprised if you
have keyboard trouble or worse in a few weeks time...
▼
Posts: 229
Threads: 67
Joined: Jul 2007
I did use a quick dry electrical spray [QD-something] two days ago without any success.
The machine was still a little wet with WD when I inserted the batteries, and it came on. It's still working.
I was also having a problem with the decimal button. It wasn't springing back quickly, so earlier today I used a pump at the tyreshop to blow some air into the button while playing with it. Now the button works much better than before.
I guess I'll have to wait a couple of weeks and see what happens.
▼
Posts: 229
Threads: 67
Joined: Jul 2007
Tom, I did connect a paperclip to both terminals before I sprayed it. I believe that is when it went out for good and couldn't be revived.
I am not sure if that's what you mean by shorting the terminals.
▼
Posts: 15
Threads: 6
Joined: Jan 1970
WD-40 inside electronics...glad it worked but ouch in the long run. I use WD-40 for the original purpose, Water Displacement. After power washing out-door equipment or an engine block, spraying WD will seperate the water film from the metal and the above mentioned waxy film will help seal the surface from water...similar to the grease (whose name escapes me) that guns and machinery are packed in.
▼
Posts: 1,788
Threads: 36
Joined: Aug 2007
Miguel, that be cosmolene..... mmmm mmmm good.
Posts: 1,162
Threads: 26
Joined: Aug 2005
Yes, of course WD was originally 'Water Displacement' (or something similar). I will admit to owning a can of WD40, which I use to keep the rust off garden tools,
the pile of steel rods/bars I have for metalwork, etc. It's also good for car ignition systems, of course.
But IMHO, it is not a good lubricant or cleaning fluid, certainly not for precision machinery or electronics.
People have this idea (based, alas on some _very_ misleading advertisements for WD40) that it'll fix just about anything.
So I see cameras, clocks, VCRs, that have been soaked in WD40. At which point they need a _complete_ strip-down, every part cleaned, some parts probably
replaced, and then I have to fix the original fault on top. It would have been a lot simpler just to fix the fault, of course.
Posts: 1,153
Threads: 94
Joined: Mar 2006
Which brings up the subject of the "Minimal Complete Toolkit".
I think a pair of channel-lock pliers, a roll of duct tape, and a can of WD-40 just about does it. ;-)
▼
Posts: 16
Threads: 4
Joined: Jan 1970
If it moves and it shouldn't, use duct tape.
If it doesn't move and should, use the WD-40.
The channel locks are what I call "motivation."
▼
Posts: 1,788
Threads: 36
Joined: Aug 2007
Sounds like the old adage: If it jams, force it. If it breaks, it needed fixing anyway.
Posts: 1,162
Threads: 26
Joined: Aug 2005
Obviously my definition of 'complete' is rather different to yours. My minimal toolkit (the tools I take to look at/repair somebody else's machine) includes
a temperature controlled soldering iron, flat-plade screwdrivers from <1mm up to about 7mm, nutdrivers from 1/8" to 1/2" (and equivalents in metric),
Phillips, Pozidriv, JIS crospoint screwdrivers, hex keys from 0.05" to 1/4" (and metric equivalents), Bristol spline keys, Torx drivers from TX3 to TX30,
a solder sucker, pliers, end and side cutters, pin chuck, trim tools, multimeter, HP LogicDart, and probably more that I've forgotten.
As I said, that's the _minimal_ toolkit :-)
▼
Posts: 1,322
Threads: 115
Joined: Jul 2005
yes, but do you prefer a 2 or 3 pound hammer?
Posts: 16
Threads: 4
Joined: Jan 1970
Tony,
What you forgot was the ASD wrist strap.
|
