Thanks, I'll take a look.
Harvey
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On 1/26/2021 11:40 AM, Carl Hallberg via groups.io wrote:
Voltage Range Switches.
I have repaired both voltage switches some time ago.? I will send pictures to io groups by Friday as I have to search for them.? A metal washer, three stainless (could be any metal screw) steel screws filed to produce half diameter, and nuts.? Tried to glue them, but didn't work.? This will last a lifetime using metal, but takes some work. I didn't look to see if this would be ok for time/division switch.? Not responsible if you try this.
Carl Hallberg (W9CJH)
On Tuesday, January 26, 2021, 09:44:35 AM CST, Harvey White <madyn@...> wrote:
The only thing I'd worry about with the LI cell would be the hash from
the stepup converter.? You can get a small charging board (or a cell
holder/voltage output/charger board in one unit, 5 volts, or 12 volts.
I have a 3D printer, so I can make a support framework for holding the
battery and bring out the 5 volts.? I could also easily put in a 5V LDO
and then run the whole scope from 9-12 volts and not have to worry about
the input voltage.
I may have to look at fixing that range switch, it's bad in one
channel.? Easier to replace the board, though.
Harvey
On 1/26/2021 1:31 AM, John Gord via groups.io wrote:
Harvey,
For power, you might want to consider what I did:? I converted the power cord storage compartment (with the little door) into a battery holder for an 18650 LiIon cell, then put a battery protection board and boost converter in place of one of the internal NiCd packs.? You need? dummy frames to give the structural support of the original NiCd packs.
Its easy to carry extra 18650 cells and just charge them elsewhere.
I don't have any leads on a replacement vertical board, but I was able to repair a damaged vertical range switch.? I don't remember what was wrong with it.
--John Gord
On Mon, Jan 25, 2021 at 06:06 PM, Harvey White wrote:
I have a 214 that I bought a number of years ago.? It had bad batteries,
no probes,? a broken store/normal/reset switch, and (as I find out) a
bad channel A vertical gain switch.
Fixed the batteries by installing another set of NiCD batteries. Not
impressed with the charging circuit and will likely (eventually) do
something about it.
Probes I could fix by taking the peltoler connections out to BNC
connections, and sacrificing the double insulated capability of the
scope.? That would be a definite reason to change the NIMH charging
circuitry away from AC line.? A 12 volt charger would do the job, or
covert to Liithium, in which case a 7.2 volt pack might do just nicely
(6.5, 7.2, might be close enough with a bit of tweaking).? The broken
store/reset switch has been replaced by one from Qservice a number of
years ago.
This leaves me with the channel A problem.? Some of the ranges (I
suspect the switch) are dead.? While I could tweak the switch a bit I'd
rather (for the sake of simpler repairs) get a new vertical board.
If not, then I need to fix that switch (and hope that I can get the
storage voltages correct....).
Suggestions?
Harvey
