Thank you, Mike.?
In terms of removing the arm from the switch stub (see pics enclosed a few messages down), where HP decided to use this brown resin to glue them together (completely unnecessary, in my opinion - how about a cable tie or something easy to remove and replace?...), what would be some recommendations in handling this? Specifically, safely and non-destructively detaching the arm from the stub. The arm is marked: "SPREAD JAWS TO INSTALL AND REMOVE," but due to the resin, that was just about impossible upon my examination when doing this.? - Can anyone determine or have some educated?guess regarding what sort of glue or resin that'd be? I tried seeing if I could scrape it or shatter it off, to no avail. It's tough and very hardened in place. Much?harder than either of the two plastics it joins.?
- Solvents? I'd be pretty weary using liquid chemicals over the main board, but maybe something is recommended and safe to use in a situation like this.?
- What else would?work? I assume others may have had this problem?and came up with some good solutions.?
Thank you, Radu.?
On Mon, Mar 3, 2025 at 8:32?AM Michael Bafaro via <m.bafaro= [email protected]> wrote: Radu, ? I wish you luck finding a replacement for the line filter and switch. ? Mike ? ? Mike, This is unrelated with the issues I'm having with the -12V rail. When disassembling/reassembling the scope, the EMI Filter?(more specifically, its built-in switch) and the HP arm/button broke apart. I can now either try to find replacements, or just replace?the EMI Filter with a unit having the switch accessible from the back of the scope (this type is relatively easy to find) and disable the actuation of the front button.? ? On Mon, Mar 3, 2025 at 8:16?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Radu, ? The pictures you sent appear to be the AC line filter (EMI) and the power switch and perhaps the line fuse.? If one of the supplies is off and the others are working, then the problem is somewhere else.? ? The display is a standard magnetic deflected CRT.? I worked in that group years ago at Motorola. ? Mike Bafaro ? ? Two steps forward, one step back (one and a half?).? While other things have been progressing, the power switch stopped?working once I put?most of the?unit back together. I enclose some pictures, but it's a typical flip flop type where a pin prods and finds two different locations between the?two states ON/OFF. I guess I can either look for a replacement (does anyone have one?), or try to repair it. Repairing something like this hasn't been something?I've had a lot of luck with - if anyone has some good tips, I'll take them happily - and then there's also the way the longitudinal arm (actuating the pressing of?the button on the front panel all the way to the back) is supposed to be handled. It seems to be glued with some hardened resin or something similar. In retrospect, though the SM doesn't mention this, I think the arm should be detached before removing the rear panel and moving it around. It puts too much pressure?and torque on the switch to take this easily and not get damaged.? Thank you for any pointers.? ? On Sun, Mar 2, 2025 at 3:20?PM Radu Bogdan Dicher via <vondicher=[email protected]> wrote: Razvan, Thank you very much, this is very helpful.? I've managed to rig a load - I had a couple of 1ohm/10W Vishay RS10s (bulletproof, in my experience), and it looks like the -12V rail is MIA because of something going on in the PS. If I can confirm?this, this would be great news (as opposed to tracking some failed tantalum decoupler or something else on the main board....).? ? Hi Radu,
I think the PSU in all 545xx series was made by Boschert Inc. and
someone already reverse engineered it. I attached the file.
I hope it helps.
Regards,
Razvan
On 02/03/2025 23:33, Radu Bogdan Dicher via wrote:
> Going back to my -12V rail issue, the SM advises loading the 5.20V rail
> with a 2ohm/25W resistor. The only way I can put something similar
> together with what I have at hand is using these dummy loads I am using
> when repairing audio amplifiers, which are a pair of 8ohm/100W non-
> inductive resistors. By paralleling?them I can load the 5.20V rail with
> a 4ohm resistor.
> What are some thoughts regarding whether this would be a suitable load
> for the PS? I think the PS just needs a low ohmic load of sufficient
> dissipation capacity and it should crank itself up to nominal, but maybe
> there's an aspect I'm overlooking.
> Thank you,
> Radu.
>
> On Sun, Mar 2, 2025 at 1:52?PM Radu Bogdan Dicher via <> > <vondicher=[email protected] <mailto:[email protected]>>
> wrote:
>
>? ? ?One of the two scopes is completely disassembled - head exploding
>? ? ?emoji - and I have the old battery desoldered after confirming?it's
>? ? ?fully depleted.
>
>? ? ?I enclose pics with what I'm using for replacement. I probably would
>? ? ?have been fine going with a 2032 type, but the 2430 I ended?up
>? ? ?fitting just right (maybe a bit snug), and the pins of the holder
>? ? ?actually match the PCB eyelets. So all is good.
>
>? ? ?I couldn't figure out what exactly was the original battery model,
>? ? ?as it's not legible even after removing the top tab, but its
>? ? ?diameter is a bit over 23mm.
>? ? ?I think this should work OK.
>
>? ? ?Back to the?actual troubleshooting now!
>? ? ?Radu.
>
>? ? ?On Fri, Feb 28, 2025 at 6:21?PM Roy J. Tellason, Sr. via
>? ? ?<> <roy=[email protected]
>? ? ?<mailto:[email protected]>> wrote:
>
>? ? ? ? ?On Thursday 27 February 2025 04:09:31 pm Radu Bogdan Dicher via
>? ? ? ? ? <> wrote:
>? ? ? ? ? > One other unfortunate effect of the spot-welding of the top
>? ? ? ? ?tab is that the
>? ? ? ? ? > battery code is not visible. I can probably destroy the
>? ? ? ? ?battery once out,
>? ? ? ? ? > and read the CRxyzt battery code, but would anyone have good
>? ? ? ? ?info offhand
>? ? ? ? ? > on it?
>
>? ? ? ? ?You might find bits of this useful:
>
>? ? ? ? ? <>? ? ? ? ?>
>
>? ? ? ? ?Scroll down to where they discuss coin and button cells:
>
>? ? ? ? ?"IEC designation numbers indicate the physical dimensions of the
>? ? ? ? ?cylindrical cell. Cells less than one centimeter in height are
>? ? ? ? ?assigned four-digit numbers, where the first two digits are the
>? ? ? ? ?diameter in millimeters, while the last two digits are the
>? ? ? ? ?height in tenths of millimeters. Taller cells are assigned five-
>? ? ? ? ?digit numbers, where the first two digits are the diameter in
>? ? ? ? ?millimeters, followed by the last three digits indicating the
>? ? ? ? ?height in tenths of millimeters."
>
>? ? ? ? ?So the size of the battery will give you the info that you need.
>
>? ? ? ? ?--
>? ? ? ? ?Member of the toughest, meanest, deadliest, most unrelenting -- and
>? ? ? ? ?ablest -- form of life in this section of space, ?a critter that can
>? ? ? ? ?be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet
>? ? ? ? ?Masters"
>? ? ? ? ?-
>? ? ? ? ?Information is more dangerous than cannon to a society ruled by
>? ? ? ? ?lies. --James
>? ? ? ? ?M Dakin
>
>
>
>
>
>
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