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Re: The first International Mail was delivered today

 

Mine arrived today, Hertfordshire, UK

Many thanks Dennis.

Jim G8NVF
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

 

Hi Larry,
Am I "CH *"? If so, I have sent you an email to your personal address, stating my interest, postal address in the UK and willingness to pay. Can you confirm that I am on your list? In which case I will send the money to you via PayPal as soon as I can.
Colin

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Larry McDavid
Sent: 12 January 2021 22:10
To: [email protected]; Tek500 Mail List (New:Groups.io)
Subject: Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Ok, folks, I now have finalized the cost of the board sets and domestic
packaging and shipping cost. Because the number of participants
increased, Jared and I were able to get the four-board set price reduced
to US$26; this is a significant improvement from the original estimate
of $38! And, these will be good boards with gold plating and
connector-edge chamfering on the main board, similar to what you see in
the YouTube video; the board color will not be black, as that is a cost
adder.

All I'm doing is aggregating requests for board sets and distributing
those board sets; no components are included in this group purchase.

So, the final price will be:

Board Set (four boards) $26
Packaging/Shipment CUSA $10
Total for CUSA $36

If you requested more than one board set, I can combine packaging and
postage for two sets only; if you requested more than two, plan for two
board sets per package.

For international, I have postage costs only for UK and Australia so far:

UK postage US$25 plus $5 packaging, total with board US$56
Australia US$28 plus $5 packaging, total with board US$59

I will have to check further for other international postage and I will
contact you individually.

Payment by PalPal Friends and Family, please! Use my email address as my
PayPal account name: lmcdavid at lmceng dot com. You should find my
email address in this message header.

There is too much cost here for me to place this board order in advance
so please pay now. In fact, there may be a conflict with Chinese New
Year so please pay promptly.

Verify your name initial is on the list below to be included. If your
name has an asterisk (*) beside it, I am missing information you must
provide very soon or risk being removed from the list. There are
additional requesters waiting for inclusion...

ML
ML
ML
PA
SM *
DC
HB
GL
MH *
JRe
WR
JT
EW
EW
EW
EW
RD
AW
SG
DS
JF
MU
PE
SN
SC *
AAlt *
BHu
EPa
WS *
KT
RDD *
PMu *
GM *
CC *
BHe *
BK *
LR *
MPe
MPe
MPe
SA
BG *
JK *
AAin *
PTC
PD *
BO
JG
EP
BL *
CT
MD
RLG
CB
CH *
DM
AD
JRa
JRa
CR
PM
SW
JW
DP
DG *
HV
BH
EL
TP
TP
LM

The following have asked for inclusion in the group order after entry
was closed. If any of the above don't provide address info or don't send
funds promptly, the following will be offered the opportunity in the
order shown below.

MLe
CO

Larry McDavid


On 12/31/2020 11:27 AM, Jared Cabot via groups.io wrote:
Hi all,

I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around.
I updated the design somewhat and designed it for simplified construction (Not a single wire to strip and solder!) and I thought someone here might be interested in taking a look or even building one themselves.
Here's a link to the youtube video:


And here's a link to the google drive with all the gerbers and schematics and stuff. I went so far as to rewrite the manual with the alterations and corrections included.


Direct link to the new manual:


Let me know what you think, and let me know if you see any errors that need correcting. :)

Regards
Jared.


--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)
Re: T912 storage oscilloscope - No 2.7 KV high Voltage

 

Attilio,

You say 'CR468 diode continues to boil', which implies that something is drawing too much current from the -120V supply. Which capacitor did you change? Can you measure the voltage across R469 and maybe check that the value of R469 is reasonably close to 1.2k? If this excess current is going to the storage board (rather than a leaking C469) then something will probably be very hot. It is not safe to touch components while the board is powered since there is 220V (and +335V!) in places but you can check that the -120V and -220V (and also +335V) have decayed a few seconds after the scope is turned off and then try touching a few components. I would start with Q942, Q944, Q946 and Q948.

Be very, very careful about not touching the parts which have high voltages (ie more than 50V) on them!

Regards,

Roger
Re: T912 storage oscilloscope - No 2.7 KV high Voltage

 

Do you tried to disconnect the rear socket of CRT? Just to be sure there isn't some internal short.

Max
Re: T912 storage oscilloscope - No 2.7 KV high Voltage

 

Greetings to all,
i replaced Q458 but nothing has changed.
I checked the voltage and frequency on the collector of Q458 with the HV diodes CR463 and CR465 disconnected: the frequency is 54 kHz and the voltage around 336 Vpp.
I also measured the voltage + 120V UNREG and it is +151 Vdc; on the collector of Q446 there are 5.3 Vdc, while on the emitter of Q454 there are 5.99 Vdc, the voltage + 8 V is + 7.98 Vdc.
On the output line from the T460 transformer I replaced a 0.1 uF capacitor towards ground but the CR468 diode continues to boil, if I remove the capacitor the diode remains cold and the voltage at - 140 Vdc (instead of -120 Vdc).
If I connect the HV CR463 and / or CR465 diodes there are no - 2.7 KV and the voltages of -120 Vdc and -220 Vdc drop to about - 14 Vdc.

I don't understand where the fault is, maybe it is the T460 transformer that is fault ?

Thanks for the attention

--Cheers
Attilio
Re: Update on Domestic US Book Delivery Dates

 

My copy arrived in Detroit 48206 yesterday. Thanks again, Dennis!
Re: The first International Mail was delivered today

 

On Wed, Jan 13, 2021 at 02:47 PM, Dennis Tillman W7pF wrote:


Another one is out for delivery this morning in The Netherlands.
Hello Dennis,
My book arrived this very morning, so NL is covered now...

Today is my birthday and .... when I told my wife several months ago about the book and that you were offering to send these books around the world, my wife offered to give one to me as a birthday present! Tell me about coincidence!

The book arrived in less than a week and is in as great shape as when sent, i.e. perfect. I like its beautiful, classic hard cover in maroon, black and gold.

I think a short expression of appreciation for the USPS is appropriate since they're having a rough ride and still succeed in delivering these books in a short time, both nationally and internationally. And no, I'm not forgetting Dutch Post (Post NL), for Leo's book and mine.

Thank you very much for all your efforts!

Raymond
The first International Mail was delivered today

 

The first of the international shipments of Peter's books was delivered this
morning in The Netherlands.
Another one is out for delivery this morning in The Netherlands.
The one that went to Japan is waiting to clear Customs in Japan.
Two that were sent to the United Kingdom arrived in Heathrow yesterday.
Two that were sent to Australia are in Japan waiting for a connecting
flight.
Re: Tek 576 step generator problem

 

Hello,

thank you very much guys for your help!
So it looks like my step-gen performs ok and like Michael Lynch said it seems to be normal that the waveform flickers a bit more @ 2, 4, 6, 8 and 10 steps.

Anyway i ran into another problem (or is it a problem?!) ... Maybe someone can do another (pretty easy) check/comparison
I shorted the C and E terminal, set the vertical range to 5uA and turned up the collector supply to have 2 divisions (10uA). When i change the vertical range now from 5uA to 10uA the reading is not 10uA but suddenly almost 75uA.
Is that normal due to internal change of measurement resistor?

5uA-Range:


10uA-Range without changing collector supply:


BR,
David
Re: 1s1 on ebay

 

If you go by eBay prices, buying two 8416s will bring that "bargain" 1S1 in line with the 200$ range I see for 1S1s these days,
Re: 1s1 on ebay

 

Woops, well that explains the price. I hope the buyer noticed.
Re: 1s1 on ebay

 

Of course, the two missing 8416s, no doubt sold off to AudioPhool Land,
Would take some of the Fun out of it....

Mark

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of snapdiode via groups.io
Sent: Monday, January 11, 2021 8:47 PM
To: [email protected]
Subject: Re: [TekScopes] 1s1 on ebay

Wow, you don't see many 1S1s these days, and not at that price! At best the unit still works, otherwise I predict in a few weeks we'll get a new member with many questions about getting a 1S1 to work.
Re: 2mV and 5mV ranges read the same on 2236

 

Raymond,

It's hard to tell without removing the cover, but I think that R26 and R76 are compact metal cans with a plastic insert for the wiper. I think I know that kind that you're talking about, but I don't see any of those in this machine. It's all either metal cans with a plastic screw head on top (like a TO-18 or TO-39 package) or Bourns blue box trim pots, as far as I can see.

Also, I opened the scope up and tried twiddling the 2 mV trim pots while feeding in a signal to see if the trace changed at all and got nothing. I'm guessing that I need to take out the attenuator board and clean the switches, which is more work that I really wanted to do on this scope at this time.

-- Jeff Dutky
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

 

There is a BOM in the user manual if you follow the google drive link in the first post or check out the file section on this mailing list.
Let me know if I forgot to add something! :)

Jared

On Wed, Jan 13, 2021 at 05:09 AM, David C. Partridge wrote:


I'd like to check that a 5000 series 'scope plug-in will work as a suitable
case for this project.

Is there an Excel SS with the BOM ?

Thanks, David
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

 

That is likely Lyle Bickley, Computing Guru of the First Order!

Mark

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Larry McDavid
Sent: Tuesday, January 12, 2021 3:43 PM
To: [email protected]
Subject: Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Who send board set payment from "Bickley Consulting West Inc.?"

Folks, if you send funds from another name, you must tell me who the
funds came from.

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)
Re: 1s1 on ebay

 

I also own four! We're twins! I also have one that barely works, the rest are just too much trouble to get working. One of them needs a deep cleaning too.

I have found myself stumped by the -139/-138V system.
Re: Grid Bias Adjustment on 475A

 

Thanks for that, David.

Raymond
Re: 2mV and 5mV ranges read the same on 2236

 

On Wed, Jan 13, 2021 at 01:00 AM, Jeff Dutky wrote:


I did have trouble with another of the trim pots on the sweep/timing board
(R754). I thought I was going to need to replace it, but as soon as I tried
adjusting it it came back to life. I'll try that here too, before start
removing boards and ordering replacements.
Hi Jeff,
The trimmer I was referring to is a flat model with a grey plastic wiper with a metal contact fixed underneath. The plastic part has a shaft, extending through a hole in the ceramic body. Underneath that ceramic body, the protruding part of the shaft at manufacture is molten to a flat disk, forming something like a mushroom causing the metal contact to exert pressure on the resistive trace.
I've seen that flat part broken off on more than one occasion so the wiper is no longer pressed against the ceramic resistive body.

Raymond
Re: 2mV and 5mV ranges read the same on 2236

 

Raymond,

I did have trouble with another of the trim pots on the sweep/timing board (R754). I thought I was going to need to replace it, but as soon as I tried adjusting it it came back to life. I'll try that here too, before start removing boards and ordering replacements.

-- Jeff Dutky
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

 

Who send board set payment from "Bickley Consulting West Inc.?"

Folks, if you send funds from another name, you must tell me who the funds came from.

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)
32581 - 32600 of 208747