Hello, I wonder if someone can help me?
I have a TEKTRONIX AM700 which I brought dead, originally, it was tripping the mains, this was some RIFA filter caps, once replaced, the AM700 now powers up. But now I have a new issue, the unit powers up, starts to boot with the splash screen, then I get a screen with a number of garbled boxes, then all the lights on the front of the unit turn on and it resets.
Things I have tried :-
Tried to activate the low level tests (Holding ¡°Menu¡± or ¡°Limit¡±) and to try and go straight into an application but crashes shortly after the splash screen or diags screen
Modding the DALLAS DS1286 as the battery was dead, no change 3V second battery OK.
Running the processor board on its own with none of the lower boards connected, same outcome.
Removing the NVRAM :- Causes the unit to display an error and Continue / Pause / Esc option, no matter which I try, I still cant activate a low level diagnostics
Removing the FLASH starts the low level diagnostics, to which it passes Board Program Reg, Board Status Reg, Spurious Interrupts, Dynamic RAM, then it gets to the FLASH which it recognises it¡¯s not present and restarts
Checked the + and ¨C 5 and 15V rails, all good, TP1 says its 12V but that¡¯s sat at 4.8V, looking at the diagram, I suspect that the only time this is 12V is if the FLASH RAM is being programmed, I could be wrong but it seems to make sense.
Things I have not tried :-
Firmware update via the floppy, though I don¡¯t have the disks, there¡¯s no way of doing this as the low level diagnostics screen pops up and then it resets, giving no ability to select that option
Reset the NVRAM, for the same reason I cant access the Frimware upgrade screen
Recapping, now this is something I haven¡¯t done because I haven¡¯t got the right caps in stock but they are on order, there is clear evidence that the silver SMD types are leaking, but as the fault is persistently the same, I have my doubts the caps are the culprit (But most certainly need replacing). You can see a damp circle around them and there¡¯s some signs of light corrosion, there¡¯s nothing serious looking to suggest corroded tracks.
Attempted to flash the boot ROMS ( Not sure if I can as I don¡¯t think I have the correct programmer)
Though I plan to replace the suspected caps, I am wondering if anyone may have had the same issue and know some other things to try?
Many Thanks
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Re: OT: microwave oven blows fuse
I had a microwave that had the opposite problem - it would only work when the door was slammed shut. I found that a flimsy steel bracket holding part of the interlock assembly had deformed over the years, and bending it back into alignment fixed it right up. After that, a gentle push and click was all it took, or slamming was OK too - it just worked like it was supposed to when new. You may want to check out the mechanical alignments of the pieces and mounting structures.
Ed
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Re: Tek 577 restoration -- help needed
The green and white wire is in the main frame of the 577. On the back of the main switch voltage and resister selector control. EXTREME CAUTION is needed here there can be 1,600 Vdc on that switch no matter what the front panel settings are. This gets the 4 voltages off the collector supply regardless of switch position. Make SURE (TRIPPLE CHECK) the variable collector control is at 0% (all the way counter clockwise)
Zen
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Rogerio O Sent: Monday, December 20, 2021 7:30 PM To: [email protected]Subject: Re: [TekScopes] Tek 577 restoration -- help needed Trying to start the calibration of the 177, but there is no voltage reading on the DMM connected as required and I turn the offset Multi. I will have to check if it is present at U350/U360 in the step amplifier. By the way, does anybody know where in the schematics is located this White /Green wire connected to the MAX PEAK VOLTS switch? This location is used in several calibration steps of both the 177 and the 577. I since I am experiencing problems with calibration it would help to diagnose the deviations I am observing if I could follw the procedure on the scematics. Thanks to all, Roger
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Re: Tek 577 restoration -- help needed
Trying to start the calibration of the 177, but there is no voltage reading on the DMM connected as required and I turn the offset Multi.
I will have to check if it is present at U350/U360 in the step amplifier.
By the way, does anybody know where in the schematics is located this White /Green wire connected to the MAX PEAK VOLTS switch?
This location is used in several calibration steps of both the 177 and the 577.
I since I am experiencing problems with calibration it would help to diagnose the deviations I am observing if I could follw the procedure on the scematics.
Thanks to all,
Roger
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Re: OT: microwave oven blows fuse
Thanks, Dave.? I'll give it a shot.? ? ? ?JimSent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: Dave Daniel <kc0wjn@...> Date: 12/20/21 1:16 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] OT: microwave oven blows fuse is what I have found to be useful more often than not.DaveD> On Dec 20, 2021, at 15:16, Glenn Little <glennmaillist@...> wrote:> > ?Do a search for microwave oven parts,> There are other vendors for parts.> > Glenn> >> On 12/20/2021 11:47 AM, Jim Ford wrote:>> Aw, crap!? I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven! It's considered a throwaway item...>> >> So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time.? Regardless, slamming the door is banned for life!? (Good luck with 2 teenage boys in the house)>> >> Unless somebody has a better idea....>> >> Thanks.>> >> Jim>> >> ------ Original Message ------>> From: "benwetzel via groups.io" <benwetzel@...>>> To: [email protected]>> Sent: 12/18/2021 9:45:17 AM>> Subject: Re: [TekScopes] OT: microwave oven blows fuse>> >>> You will need to replace the plastic bracket that holds all of the switches.? Or easier approach is to>>> get the whole interlock assembly.>>> >>> Good luck sir.>>> Ben>>> >>> >>> >>> >>> >> >> >> >> >> > > -- > -----------------------------------------------------------------------> Glenn Little??????????????? ARRL Technical Specialist?? QCWA? LM 28417> Amateur Callsign:? WB4UIV??????????? wb4uiv@...??? AMSAT LM 2178> QTH:? Goose Creek, SC USA (EM92xx)? USSVI, FRA, NRA-LM??? ARRL TAPR> "It is not the class of license that the Amateur holds but the class> of the Amateur that holds the license"> > > > > >
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Re: Internal Drive Mechanism for 7B53N (et., al.) Sweep Speed Cam
I'm happy to report that the cams are reassembled in the plugin and they are working exactly as they should. Thanks to all who replied.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Barry" <n4buq@...>
To: "tekscopes" <[email protected]>
Sent: Monday, December 20, 2021 9:59:14 AM
Subject: Re: [TekScopes] Internal Drive Mechanism for 7B53N (et., al.) Sweep Speed Cam The way this works for this particular rear drum is that the two splines drive
the drum, regardless of whether it's in delayed sweep or normal sweep mode.
Those splines also allow the shaft to be pulled forward such that when the
knob is pulled far enough to disengage the pin that ordinarily locks that knob
it to the larger ringed knob (the one that rotates the forward drum for the A
or MAIN sweep), rotating the smaller, gray knob still causes the rear drum to
rotate independently of the front drum thus allowing two sweep speeds.
I'm reasonably sure no one has been into that rear drum since it left Tektronix.
If they had been, I doubt they would have glued it back together without
gluing the broken drive mechanism parts too.
I looked around a bit on eBay from other examples and I think I see where the
style of drive mechanism to which you're referring is shown.
I'm letting the glue cure where I glued the end cap to the drum. After that
cures, I'll reassemble the entire cam assembly and report back.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Jim Adney" <jadney@...>
To: "tekscopes" <[email protected]>
Sent: Monday, December 20, 2021 9:44:05 AM
Subject: Re: [TekScopes] Internal Drive Mechanism for 7B53N (et., al.) Sweep
Speed Cam On Sun, Dec 19, 2021 at 05:32 PM, Jim Adney wrote:
I don't see anything in your photos that resembles the drive dog that I'm
familiar with. I may have been too quick to respond here. There's something with a ~1/4"
diameter pushed right up against the retaining washer. Your photos don't show
what the other end looks like, but it may be the drive dog that I expected.
Yours appears to be clear plastic, while the ones I've seen were the same
material as the drums.
Does that dog body rotate with the shaft? If so, does it still have dogs that
engage the slots in the hub?
Something seems wrong about the parts in your photo, because those parts should
simply slide out of that hub right now. Perhaps someone has glued them all
together, so the dog body is glued to the hub and the shaft just slides in the
body. Or perhaps the dog body is rotated so that the dogs are no longer aligned
with the slots in the hub.
I was not familiar with the "glue method" mentioned earlier. That could work if
the dog body was simply loose on the shaft, but it would have been much simpler
to pull everything out and glue the body to the knurled portion of the shaft.
The dog body will slide out the end if the dogs are aligned with the notches in
the larger hole. I'm quite sure that Tek did NOT assemble that part and then
glue the drum around it. If you look at the parts list, Tek shows only complete
drums and complete shafts w/dog bodies. Neither would have been useful if the
drums were glued together after inserting the shafts. The 2 slots on the sides
of the larger hole in the hub, visible in one of your phots, are also evidence
that this was designed to clear the drive dog body. If the drum was expected to
be glued around the dog body, the holes on both ends could have been simple
1/8" round holes.
My impression is that the retaining washer should have been on the other end of
the drum. It looks to me like someone has been in here ahead of you. That would
explain a lot.
My prior experience is a couple decades old, so forgive me if my memory is
imperfect.
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Re: OTish: ROM/RAM bank switching in the 2467 et al.
On Mon, Nov 29, 2021 at 1:06 PM Sigur?ur ?sgeirsson <siggi@...> wrote: On Sun, Nov 28, 2021 at 4:40 PM Mark Litwack <mlitwack@...>
wrote:
I think writing an emulator would be a monumental task considering all
the hardware registers that can affect the execution path. I think it
would be easier to hook up a logic analyzer and work on the real thing.
All the state inputs for the analyzer are exposed and can be probed
directly (like the ROM and PAGE signals). I've done this on several
occasions for the 2465 and the 2445A to try to learn how some of the code
works.
I guess it depends on what sort of tools you're used to working with. I'm
a "recovering software engineer", so my handiest hammer will probably
always be software. I've looked at MAME, which is primarily used to emulate
arcade games, but it has all the infrastructure already made for building
an emulator, so to build an emulator for the 2400 scopes would be mostly
about writing up the register emulation. It doesn't look too daunting from
afar :).
So I started writing a MAME driver for the 2465, since it's "uncomplicated" in terms of memory accesses. I discovered that there are actually several tek device drivers in MAME already, notably Driver tek4051 (Tektronix 4051): Driver tek4052a (Tektronix 4052A): Driver tek4107a (Tektronix 4107A): Driver tek4109a (Tektronix 4109A): I don't know to what level of completion or accuracy these devices are emulated. In any case, my embryonic emulator is currently stuck in initialization, where it appears the firmware is wiggling DAC levels while polling the display sequencer for trigger status. Presumably this is the self-test that validates triggering against the line input. I have a vague recollection of a power-up hang in these scopes when the display sequencer or the trigger hybrid are bad. Does anyone here remember this sort of powerup hang?
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Re: OT: microwave oven blows fuse
Don't ignore ebay for appliance parts. Easy to search and with pictures. Made in Asia and zero cost to advertise has done wonders for consumer replacement parts availability.
Eric WB6KCN
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Randy.AB9GO Sent: Monday, December 20, 2021 2:37 PM To: [email protected]Subject: Re: [TekScopes] OT: microwave oven blows fuse Go on the internet and look up Dayton appliance parts or Cincinnati appliance parts.com. They've been very good about having parts for anything I've needed over the years. Take anything you receive from a 1-800 number for Whirlpool with a boxcar full of salt. They usually don't know what they're talking about. -- Thanks, Randy. randy.ab9go@...
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Re: OT: microwave oven blows fuse
Go on the internet and look up Dayton appliance parts or Cincinnati appliance parts.com. They've been very good about having parts for anything I've needed over the years. Take anything you receive from a 1-800 number for Whirlpool with a boxcar full of salt. They usually don't know what they're talking about.
--
Thanks,
Randy.
randy.ab9go@...
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Re: OT: microwave oven blows fuse
My dim memory is that U.S. manufacturers are required to support products for five years. We certainly live in a throw away world.
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On 12/20/2021 2:05 PM, Geoffrey Thomas via groups.io wrote: As posted elsewhere, manufacturers in Europe have to hold spare parts for 7-10 years after product purchase, and not before time.
Geoff.
On 20/12/2021 16:47, Jim Ford wrote:
Aw, crap!? I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven!? It's considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time.? Regardless, slamming the door is banned for life!? (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
------ Original Message ------
From: "benwetzel via groups.io" <benwetzel@...>
To: [email protected]
Sent: 12/18/2021 9:45:17 AM
Subject: Re: [TekScopes] OT: microwave oven blows fuse
You will need to replace the plastic bracket that holds all of the switches.? Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
--
Richard Knoppow
dickburk@...
WB6KBL
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Re: OT: microwave oven blows fuse
As posted elsewhere, manufacturers in Europe have to hold spare parts for 7-10 years after product purchase, and not before time.
Geoff.
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On 20/12/2021 16:47, Jim Ford wrote: Aw, crap!? I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven!? It's considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time.? Regardless, slamming the door is banned for life!? (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
------ Original Message ------
From: "benwetzel via groups.io" <benwetzel@...>
To: [email protected]
Sent: 12/18/2021 9:45:17 AM
Subject: Re: [TekScopes] OT: microwave oven blows fuse
You will need to replace the plastic bracket that holds all of the switches.? Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
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My TDS520A lost its horizontal hold recently. Half of its SMD electrolytics are still OK, incidentally.
Cause: a small 39Kohm resistor had gone high, in the megohm range. There are only two on the CRT board. The guilty one reduced the SYNC.
The same resistor was pointed to on an EEV blog notice.
Regards.
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Re: OT: microwave oven blows fuse
Greetings,
Of course, I don¡¯t know the details and having only loosely followed this interesting conversation, but two things came to mind.
My first reaction is that Kitchen aid/Whirlpool calling an appliance a ¡°throw-away¡± item is callous and obscene - let¡¯s just keep filling the planet with ¡°throw-away¡± trash.
Then, on perhaps a more productive and helpful note - can you reverse engineer the needed parts and have them 3D printed?
Wishing you a good solution, wonderful holiday, and that 2022 becomes you best year thus far and a better year for us all.
Regards,
Ken
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On 20Dec, 2021, at 9:47 AM, Jim Ford <james.ford@...> wrote:
Aw, crap! I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven! It's considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time. Regardless, slamming the door is banned for life! (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
------ Original Message ------
From: "benwetzel via groups.io" <benwetzel@...>
To: [email protected]
Sent: 12/18/2021 9:45:17 AM
Subject: Re: [TekScopes] OT: microwave oven blows fuse
You will need to replace the plastic bracket that holds all of the switches. Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
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Re: OT: microwave oven blows fuse
is what I have found to be useful more often than not.
DaveD
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On Dec 20, 2021, at 15:16, Glenn Little <glennmaillist@...> wrote:
?Do a search for microwave oven parts,
There are other vendors for parts.
Glenn
On 12/20/2021 11:47 AM, Jim Ford wrote:
Aw, crap! I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven! It's considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time. Regardless, slamming the door is banned for life! (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
------ Original Message ------
From: "benwetzel via groups.io" <benwetzel@...>
To: [email protected]
Sent: 12/18/2021 9:45:17 AM
Subject: Re: [TekScopes] OT: microwave oven blows fuse
You will need to replace the plastic bracket that holds all of the switches. Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: OT: microwave oven blows fuse
This is why the ¡°Right to repair¡± movement is important. I can understand a
manufacturer that no longer has parts for something 20+ years old (like the
old Tek 500-series!) and is the reason why groups like this are so useful.
I knew there was an interlock system in the microwave. I fixed one before
myself - the pivot bolt for the moving part of the latch was too short and
would loosen so the latch would not activate the switch. I wound up
replacing it with a NAS (aircraft) standard bolt because it was the right
size and I could hold it in place with a matching nut - and I had it in my
hardware bin. The microwave gave out long before that bolt did. What bugs
me is manufacturers who won¡¯t even sell you a manual for a current product.
I had this experience with a Miele dishwasher. Very well engineered - they
had a smart design. The main water valve was at the end of the hose that
connected to the water supply. It was a normally-closed valve of course but
unlike the usual design with that valve inside the dishwasher, if this one
failed, the water would be shut off at the supply. You don¡¯t have water at
pressure inside the supply hose. The problem was a failure in that valve. I
contacted the local Miele customer support and asked about buying a service
manual and parts list. They would not sell it to me - ¡°only for our
authorized factory repair personnel¡±. I asked if I could get it serviced -
sure, but I just had to tell them from which distributor I purchased it. I
couldn¡¯t. It was bought by the contractor who re-did our kitchen and it had
been fifteen years since then. I had no idea from whom he bought the
dishwasher and they would NOT service it unless I could prove it was
purchased from one of their ¡°authorized¡± dealers. I was not asking for
warranty service - I said I¡¯d be happy to pay for it. Nope. They
¡°protected¡± their dealers as well as their service people.
A lot of the reason I like to have service manuals for stuff I own is not
only to do simple fixes or maintenance myself, but I can quickly determine
if it is something I cannot do - either out of my capability range or
requiring specialized (and expensive!) tools.
Wound up scrapping that $1000 Miele dishwasher. I replaced it with a
Kenmore after I determined that they would sell me a service manual.
I¡¯m not trying to put service folks out of work - I think it¡¯s a minority
of folks like those on this group who are willing to put hours of work into
fixing something, so we¡¯re not a threat to repair and maintenance folks. I
did figure out that I could not repair that Miele myself even with the
manual - that valve was attached to the pipe nipple with a specialized
crimp connector; that would need the proper crimp
Here¡¯s a link to ¡°right to repair¡± legislation:
Steve Horii
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On Mon, Dec 20, 2021 at 13:47 Jim Ford <james.ford@...> wrote: Aw, crap! I just called Kitchen Aid/Whirlpool parts, and no, they don't
stock any parts at all for my "countertop" microwave oven! It's
considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the
timing of the door switches proper or just leave it as-is and hope the
fuse doesn't blow for a long time. Regardless, slamming the door is
banned for life! (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
------ Original Message ------
From: "benwetzel via groups.io" <benwetzel@...>
To: [email protected]
Sent: 12/18/2021 9:45:17 AM
Subject: Re: [TekScopes] OT: microwave oven blows fuse
You will need to replace the plastic bracket that holds all of the switches. Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
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Re: OT: microwave oven blows fuse
Do a search for microwave oven parts,
There are other vendors for parts.
Glenn
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On 12/20/2021 11:47 AM, Jim Ford wrote: Aw, crap!? I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven! It's considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time.? Regardless, slamming the door is banned for life!? (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
------ Original Message ------
From: "benwetzel via groups.io" <benwetzel@...>
To: [email protected]
Sent: 12/18/2021 9:45:17 AM
Subject: Re: [TekScopes] OT: microwave oven blows fuse
You will need to replace the plastic bracket that holds all of the switches.? Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
|
Re: OT: microwave oven blows fuse
Aw, crap! I just called Kitchen Aid/Whirlpool parts, and no, they don't stock any parts at all for my "countertop" microwave oven! It's considered a throwaway item...
So I suppose I can either fiddle with the latch to try to keep the timing of the door switches proper or just leave it as-is and hope the fuse doesn't blow for a long time. Regardless, slamming the door is banned for life! (Good luck with 2 teenage boys in the house)
Unless somebody has a better idea....
Thanks.
Jim
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------ Original Message ------ From: "benwetzel via groups.io" <benwetzel@...> To: [email protected]Sent: 12/18/2021 9:45:17 AM Subject: Re: [TekScopes] OT: microwave oven blows fuse You will need to replace the plastic bracket that holds all of the switches. Or easier approach is to
get the whole interlock assembly.
Good luck sir.
Ben
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Re: 465 Delay Time Position knob
If your scope does not have the multimeter (e. g. DM43 or 44) on top of the unit, then you should have the metal one. It has two parts; the outer ring advances with each revolution of the inner knob. The idea is to determine an accurate delay value from the knob and multiplying by the time/div setting. It¡¯s handy for written procedures and qualitative measurements but most people use it to position interesting stuff on the screen.
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5111A Horizontal BW limit.
I've been working on checking and adjusting a 5111A scope. I'm hoping to use it as the home for a 5L4N. The 5L4N needs some work, and I want to make sure the 5111A is working properly first.
I have a 5A18N and 5B10N to use in the check-out. For the most part everything has checked out very well. I also checked the 5A18N and 5B10N, so have good confidence in them. I've used them to check out a 5103N as well, which shows good BW in all 3 slots.
However, the 5111A horizontal slot is showing a BW limit of only 1.5MHz. It's supposed to be 2MHz. The vertical slots are showing 3MHz of BW.
I've taken a look at the output of the 5A18N in all three slots. Applying 10X probes to pins 7A/7B of the interface connectors does limit the BW somewhat, but the vertical slots are still making 2MHz, and the horizontal slot is still limited at near 1.5MHz. When measuring the 7A/7B outputs in the horizontal slot I can see the BW roll-off there. So it doesn't appear to be the Horizontal Deflection Amplifier. Something about the interface amplifier (Qs 820, 821, 930, 931)? My SN is B011931, so doesn't have C921.
I'm at a bit of a loss as how to proceed and isolate the issue. This scope is in nice shape - seems to be low mileage. I'm not enthusiastic about pulling components in a blind search. I'd prefer taking a more analytical approach to isolating the fault.
Any ideas or known issues are appreciated.
Dave
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Re: Internal Drive Mechanism for 7B53N (et., al.) Sweep Speed Cam
On Mon, Dec 20, 2021 at 04:44 PM, Jim Adney wrote:
I was not familiar with the "glue method" mentioned earlier. That could work
if the dog body was simply loose on the shaft, but it would have been much
simpler to pull everything out and glue the body to the knurled portion of the
shaft. The dog body will slide out the end if the dogs are aligned with the
notches in the larger hole. I'm quite sure that Tek did NOT assemble that part
and then glue the drum around it. If you look at the parts list, Tek shows
only complete drums and complete shafts w/dog bodies. Neither would have been
useful if the drums were glued together after inserting the shafts. The 2
slots on the sides of the larger hole in the hub, visible in one of your
phots, are also evidence that this was designed to clear the drive dog body.
If the drum was expected to be glued around the dog body, the holes on both
ends could have been simple 1/8" round holes.
The glue method, which (AFAIK) I introduced and performed successfully in several cases, has been successfully performed by others, some of who reported back in this Group. It is meant for those who can't take the 'scope apart, don't dare or don't think it is worth the trouble. It works in those cases where the drum, which is permanently fixed on the knurled part of the shaft during the molding procedure, breaks loose. The shaft then turns freely inside the drum. If the shaft can be pulled out through the front of the 'scope without any further disassembly than removal of the "var" knob, this is what has happened. Applying the correct procedure, a small amount of cyanoacrylate glue is applied to the knurled end of the shaft, with the remainder of the shaft being covered with a very, very thin layer of grease. Next, the shaft is reinserted into the 'scope from the front, into the drum. With the right amount of glue (not too much!), this turns out to be a seemingly tricky but successful procedure. I haven't experienced nor heard of, any failures. Because of the (tiny amount of) grease left in the tube around the shaft, the procedure cannot easily be repeated if unsuccessful. Raymond
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Eric Schumacher
Randy.AB9GO
Dave Peterson
Raymond Domp Frank