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Re: Question on probe impedance

arthurok
 

get a 6201a active probe . thats what i use

----- Original Message -----
From: Bill R
Cc: TekScopes@...
Sent: Saturday, February 10, 2007 7:46 PM
Subject: Re: [TekScopes] Question on probe impedance


Ron,

The 7A19 is a very wideband instrument. An input impedance of 1 megohm
and 20 or 25 pf would cause it to roll off to quickly, limiting its
bandwidth.

You can use a probe designed to work with 50 ohm inputs. A X 10 probe
will look like 500 ohms at the probe tip, a X100 probe will look like
5000 ohms. There are some probes out there that have switchable input
Zs for those applications where you are not using the total bandwidth.
Check one of the old catalogs.

Best Regards

Bill Roberts

HBcubed wrote:
> I have a 7A19 plugin which has an input impedance of 50 ohms. Why was
> this input impedance selected ??.(most scopes are 1M ohm). What
> happens if you use a high impedance probe with this plug in?? What is
> the "correct" probe to be used with the 7A19?
>
> Thanks for any replies.
>
> Ron Simmons
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>


Re: Question on probe impedance

Bill R
 

More, Ron -

I checked the 1975 catalog. It lists the P6056 as X10 and P6057 as X100, both working into 50 Ohm scope input. There is a super probe out there, a FET probe, P6201 that goes to 900 megaHz and terminates in 50 Ohm or 1 megOhm inputs. If you find a working one for less than $100.00, with all accessories, consider yourself lucky.

Bill

HBcubed wrote:

I have a 7A19 plugin which has an input impedance of 50 ohms. Why was
this input impedance selected ??.(most scopes are 1M ohm). What
happens if you use a high impedance probe with this plug in?? What is
the "correct" probe to be used with the 7A19?

Thanks for any replies.

Ron Simmons



Yahoo! Groups Links






Re: Question on probe impedance

Bill R
 

Ron,

The 7A19 is a very wideband instrument. An input impedance of 1 megohm and 20 or 25 pf would cause it to roll off to quickly, limiting its bandwidth.

You can use a probe designed to work with 50 ohm inputs. A X 10 probe will look like 500 ohms at the probe tip, a X100 probe will look like 5000 ohms. There are some probes out there that have switchable input Zs for those applications where you are not using the total bandwidth. Check one of the old catalogs.

Best Regards

Bill Roberts

HBcubed wrote:

I have a 7A19 plugin which has an input impedance of 50 ohms. Why was
this input impedance selected ??.(most scopes are 1M ohm). What
happens if you use a high impedance probe with this plug in?? What is
the "correct" probe to be used with the 7A19?

Thanks for any replies.

Ron Simmons



Yahoo! Groups Links






Question on probe impedance

 

I have a 7A19 plugin which has an input impedance of 50 ohms. Why was
this input impedance selected ??.(most scopes are 1M ohm). What
happens if you use a high impedance probe with this plug in?? What is
the "correct" probe to be used with the 7A19?

Thanks for any replies.

Ron Simmons


CG 5010 / CG 5011 Programmable Calibration Generator, Display fault

 

Unit origin and identification;
The unit is a Tektronix CG 5011 Programmable Calibration Generator,
serial number is B010905, option 01. Date of manufacture is probably
early 1992, from device date codes. Unit was purchased on eBay.
Repairs where done on the front panel just before this failure.

Symptoms;
I had just repaired this unit for another fault related to the front
panel assembly, AI. At power on the unit does a lamp test. In the
right hand window display the left-most character did not light up.
It used to work before that last repair.

Repair;
Remove the unit from it's power supply by pulling on the two
lock-tabs. With two tabs and many PWB assemblies connected to the
power supply, a measurably large force is required to pull the plug-in
from the power supply. Disassemble the front panel by removing all 18
screws that hold the front panel to the rest of the unit. There are 6
screws on the bottom side and 9 on the top side. You will need a
phillips type screwdriver for this. Remove the two side covers.
Gently pull on the front panel to create a small gap. Disconnect the
two pull tabs by pushing down a bit until the rear end slips out of
the mating part. Pull the front panel away some more but not too much.
You will see one or more pins that are not mated on connector
A1J1521, female header. It is at the left side of the A1 assembly,
Front Panel, and is mounted vertically. It is a 50 circuits dual row
header type connector. On my instrument pin one, the top right pin of
mating male connector on Main Interconnect Board, A2J1200, was bent
and had not made contact with the mating part on A1. Pull the front
panel further out until all the pins are free and you have some work
space. If you fold the front panel face down this should allow easy
access because all the wires are connected near the bottom. Inspect
all the connector pins and carefully bend them back into proper
alignment in both axis. Inspect the mating part on the front panel
for obstruction or defect. Install the front panel back being careful
to make sure all the pins are properly aligned. When the pins are
mated do not push in yet. Reattach the two pull tabs. If they do not
go all in, check that the small bump on the bottom of the unit, has
not caught the assembly, if so just use a small tool and push the
protrusion up into the unit to free the tab so it is pulled back by
the spring. Push the front panel so the connectors pins go straight
in. Inspect. Replace all 18 screws, you may have to push the EMC
gasket out of the way to properly insert the screws. Re-install the
two side covers. Install in a TM 5000 series power supply. Apply
power. My unit was now fully operational.

Analysis;
The mis-connected pin on A1J1521, pin 1, carries the signal for the
left-most character on display DS1501, see schematic Front Panel
Display "1" in the manual. Without any power to the display it would
not operate. Since there was no other device connected there should
be no collateral damage or parts to replace except to realign the bent
pin.

Daniel from Ville Saint-Laurent, Qc, Canada. D22dufresne ( at ) yahoo
( the usual dot ) ca.


CG 5010 / CG 5011 Programmable Calibration Generator, Broken ¡°Variable¡± Switch P

 

Unit origin and identification;
The unit is a Tektronix CG 5011 Programmable Calibration Generator,
serial number is B010905, option 01. Date of manufacture is probably
early 1992, from device date codes. Unit was purchased on eBay. The
unit was advertized as missing this knob.

Symptoms;
The "Variable" button was missing. The "Units / Div" button was
split. The worst was that the "Variable" shaft, plastic, was broken
just off the end of the "Units / Div" shaft. Both buttons and shafts
are concentric. The two function are done with a single dual
concentric switch A1SW1121. It is made by Standard Grisby of Aurora
Il, USA, for Tektronix. Tektronix part number is 260-2500-00, SWITCH,
ROTARY: FRONT PANEL, CG5010, manufacturer 80009 (Tektronix).

Repair;
Not wanting to buy another CG 5011 or a rare part for something that
could be fixable, I tried to repair it myself. I succeeded.

Remove the unit from it's power supply by pulling on the two
lock-tabs. With two tabs and many PWB assemblies connected to the
power supply, a measurably large force is required to pull the plug-in
from the power supply.

Disassemble the front panel by removing all 18 screws that hold the
front panel to the rest of the unit. There are 6 screws on the bottom
side and 9 on the top side. You will need a phillips type
screwdriver for this. Remove the two side covers. Gently pull on the
front panel to create a small gap. Disconnect the two pull tabs by
pushing down a bit until the rear end slips up and out of the mating
part. Pull the front panel further out until all the pins are free and
you have some work space. If you fold the front panel face down this
should allow easy access because all the wires are connected near the
bottom. Using a small hexagonal key remove the remaining knob.

Remove the screws that hold the assembly to the front panel proper.
Remove the assembly.

Use a 0.5 inch open end wrench remove the nut holding the switch to
the front panel. Remove the lock nut. Carefully unsolder the 6 pins, 3
per side, that hold the switch to the front panel. I used a solder
sucker and then heating the solder pad I wiggled the pins one by one
and let them cool while moving them constantly. When all the pins are
free, pull the switch out.

Clean the pins of any leftover solder. Inspect the switch. You will
notice it is made of two printed wire boards, PWBs, that hold the pins
and a plastic housing. The rear PWB is the "Variable" part of the
switch. Using a sharp utility knife cut off the 8 plastic tabs that
hold the PWB to the switch. You should be able to pry the PWB off the
switch. Remove the PWB and the rotor assembly. You may need to push
on the central shaft with a small tool or hard wire. Keep all the
parts safely. Take the broken shaft and inspect it, at the rear end
there is a small flat piece of plastic that engages into the rotor
assembly that holds the moving fingers that make contact with the PWB.
Carefully remove the rotor from the shaft.

The shaft external diameter is nominally 0.125 inch. First inspect
the shaft for any visible defect and correct them. File the front end
of the shaft flat and clean.

Locate a piece of plastic that is 0.125 inch outside diameter. I
found that the ink reservoir and dispenser of low cost pen to be the
right size. You may have to check a few different brands and models
to find one. If you are lucky the pen ink is all gone. If not, cut
it off above the two dents that hold the spring in place and discard
the ink. Hours later, when you have removed the ink from the plastic
cylinder and from yourself, your clothes and half your house, you are
ready to do some real work. By the way nail polish remover worked OK
on the ink in my plastic tube.

Use a file and file away the end on about 0.125 inch long of the
broken shaft to create a smaller shaft, concentric with the broken one
and straight so the plastic tube can be slipped at the end. I had to
redo this part, the first try was offset and crooked. When the fit is
acceptable and straight check that the new extended shaft slips easily
into the outer shaft. If not file away any bumps or obstructions.
When all is finally OK mixup a small amount of epoxy and apply to two
shafts separately and then mate. Make sure all is straight, leave to
harden as per epoxy maker instruction.

Original shaft, new smaller end, side view
¨C----------------
I--------
I I
I--------
------------------
When dry, remove any excess epoxy and check for fit again in the outer
shaft. Make sure it fits OK. Reassemble the rotor and the PWB onto
the switch. Check that all is still OK by rotating the new extended
shaft in both directions for one full rotation. The PWB should snap
tight on the switch assembly and hold tight, if not use some hot glue.
Hot glue can be removed for repairs later.

Reassemble the switch onto the Front Panel with the lock washer and
the nut. Tighten but not too much. Solder only after having
installed and tightened the nut otherwise if you solder before
installing the nut this will put mechanical stress on the soldered
connections and this is bad.

Install the assembly to the front panel with the screws.

Install the front panel back being careful to make sure all the pins
in the 50 circuits connector are properly aligned. When the pins are
mated do not push in yet.

Reattach the two pull tabs. If they do not go all in, check that the
small bump on the bottom of the unit, has not caught the assembly, if
so just use a small tool and push the protrusion up into the unit to
free the tab so it is pulled back by the spring. Find a replacement
knob for the missing "Variable". Replace the "Units / Div" knob.
Check the length of the new shaft and the new knob and cut the new
shaft to fit the knob. Install the "Variable" knob.

Push the front panel so the connectors pins go straight in. Inspect.
Replace all 18 screws, you may have to push the EMC gasket out of the
way to properly insert the screws. Re-install the two side covers.

Install in a TM 5000 series power supply. Apply power. My unit was
now fully operational.

Optional;
You could also replace the shaft completely. Remove the plastic flat
end piece on the original shaft. This flat part inserts into the
rotor. Replace the shaft has a whole, use epoxy to glue the end
piece. Easier. No filing, I hate paperwork.

Analysis;
Please do not break shafts.

Hope this helps someone.
Thanks

Daniel from Ville Saint-Laurent, Qc, Canada. D22dufresne ( at ) yahoo
( the usual dot ) ca.


SG 5010 Programmable 160 kHz Oscillator, No output

 

Unit origin and identification;
The unit is a Tektronix SG 5010 Programmable 160 kHz Oscillator,
serial number is B020944, no option. Unit was purchased on eBay.

Symptoms;
I had just purchased this unit and there was no output. Also when
pushing the output "On/Off" button and measuring the output
resistance, I would get overload on my ohmmeter. All the bottons and
display are fully operational and respond properly to any action.
There is just no output signal.

Repair;
The unit's history was unknown. Remove the unit from it's power
supply by pulling on the lock-tab.

Remove the side covers. Remove the rear, 2 hex bullet connectors 3/16
inch, and top cover, 5 screws, as a single piece. You will need a
phillips type screwdriver and an open 3/16 inch wrench for this.
Remove the two side covers.

Remove the Oscillator Board, A14, it is the one at the right of the
unit. Inspect the Output Board, A13 it is the next board in from the
right end. There is a connector at the front near the Front Panel
Board, A10, J4011, at the very bottom of the board. Check that all 3
pins are properly mated. If not remove the board and bend the pins
straight.

Carefully replace the output board, then the oscillator board, then
the top/rear covers and side covers.

Install in a TM 5000 series power supply. Apply power.

Analysis;
The mis-connected pins on A13J4011, pins 1, 2 and 3, carry the output
signal to the front panel connectors. Without a connection there was
no signal getting to the output connectors and no resistance in
parallel with the connectors as these are on the output board.

Hope this helps someone.

Regards

Daniel from Ville Saint-Laurent, Qc, Canada. D22dufresne ( at ) yahoo
( the usual dot ) ca.


SG 5010 Programmable 160 kHz Oscillator, Output Level cannot be calibrated

 

Unit origin and identification;
The unit is a Tektronix SG 5010 Programmable 160 kHz Oscillator,
serial number is B020944, no option. Unit was purchased on eBay.

Symptoms;
All the bottons and display are fully operational and respond properly
to any action. Performing calibration to adjust the output level, the
first step, I cannot adjust the output level at all, neither up nor
down. The output level is high about 15 %.

Repair;
The unit's history was unknown. Remove the unit from it's power
supply by pulling on the lock-tab.

Remove the two side covers. Remove the rear, 2 hex bullet connectors
3/16 inch, and top cover, 5 screws, as a single piece. You will need
a phillips type screwdriver and an open 3/16 inch wrench for this.

Remove the Oscillator Board, A14, it is the one at the right of the
unit. Inspect the Output Board, A13, it is the next board in from the
right end. There are two wired connectors (connector with wire
soldered to directly to the board) near the top that connect to two
transistors located on the central metal piece. Check that the
transistor nearest the front is connected to the cable that has the
wiring nearest to the front of the Output Board. The same for the
rear positioned transistor mated with the wiring harness nearer to the
rear of the unit. If not remove the board and disconnect and
reconnect the transistors properly.

Carefully replace the output board, pay close attention to the small 3
pins connector at the front and bottom of the Output Board. Replace
the Oscillator Board, then the top/rear covers and side covers.

Install in a TM 5000 series power supply. Apply power.

Analysis;
The output level adjustment is in fact the adjustment of the regulated
positive supply voltage, nominally 17 V. The mis-connected
transistors are part of the positive and negative regulated power
supplies. With the connections crossed, the transistors are fully on
and cannot be controlled by their respective regulator circuits. The
supply voltage is too high and the output level is too high and cannot
be adjusted to be with specifications.

Hope this helps someone.

Regards

Daniel from Ville Saint-Laurent, Qc, Canada. D22dufresne ( at ) yahoo
( the usual dot ) ca.


SG 5010 Programmable 160 kHz Oscillator, PLL Error, code 315

 

Unit origin and identification;
The unit is a Tektronix SG 5010 Programmable 160 kHz Oscillator,
serial number is B020944, no option. Unit was purchased on eBay.

Symptoms;
At power up, the PLL light would turn on and blink, sometimes it would
turn off and the unit would function properly at other times, the PLL
light wold stay on and ERR 315 would be displayed.

Repair;
The unit's history was unknown. Remove the unit from it's power
supply by pulling on the lock-tab.

Remove the two side covers. Remove the rear, 2 hex bullet connectors
3/16 inch, and top cover, 5 screws, as a single piece. You will need
a phillips type screwdriver and an open 3/16 inch wrench for this.

The PLL error is and indiction that the Phase Locked Loop, PLL, is not
working properly. The PLL is located on the left most board and it
controls the oscillator on the Oscillator Board, the right most board.
The signal, 2 traces, goes across connectors and traces on all the
boards in between. Any mis-connection, bad soldering, frayed cable
will interrupt the proper operation of this signal. Inspect and
correct all the cables and connections between all the boards. The
connecting pins should be clean, free of any oxidation or foreign
material, the cables should be free of any nix, cuts or frayed
insulation. Repair or replace as necessary, clean and reseat all
connections.

Replace the top/rear covers and side covers.

Install in a TM 5000 series power supply. Apply power.

Analysis;
The PLL circuit has features to detect an out of lock condition, so
it's failure is detected by the instrument. Any failure of this
circuit will cause the error message and the PLL light to be
displayed. The signal is sent over a pair of wires and connections
that are most often at the end or near the end of connectors making
these more susceptible to been open circuit if the connector is not
fully seated and is not parallel to the header.

Hope this helps someone.

Regards

Daniel from Ville Saint-Laurent, Qc, Canada. D22dufresne ( at ) yahoo
( the usual dot ) ca.


SG 5010 Programmable 160 kHz Oscillator, Output too low

 

Unit origin and identification;
The unit is a Tektronix SG 5010 Programmable 160 kHz Oscillator,
serial number is B020247, no option. Unit was purchased on eBay.

Symptoms;
Unit operates normally with 50 ohms output impedance. With 150 ohms
or 600 ohms output resistance in a 600 ohms load, the level is too
low. In balanced mode the positive output is OK, only the negative
output is affected, too low.

Repair;
The unit's history was unknown. Remove the unit from it's power
supply by pulling on the lock-tab.

Remove the two side covers. Remove the rear, 2 hex bullet connectors
3/16 inch, and top cover, 5 screws, as a single piece. You will need
a phillips type screwdriver and an open 3/16 inch wrench for this.

The output resistance can be selected from the front panel from 3
values; 50 ohms, 150 ohms and 600 ohms. This is done through relays
and resistor networks. Inspection of the relays and resistor networks
did not reveal any physically observable defects or signs of overload.
The resistor networks are on the Output Amplifier Board, A13, the
second one in from the right. Comparing the positive output network,
A13R2011, with the negative output network, A13R2012, resistor values
showed that one resistor was out of value on the negative network.
The output resistance for the 50 ohm setting is direct. For the other
two, relays add resistors in series with the 25 ohms. These resistors
are connected in parallel for the 150 ohms setting. I measured the
defective resistance and calculated the resistance value needed to
bring the value with specifications. I ended up using two resistors
soldered across the defective network element. The final value is
within 0.1 ohm between the positive and the negative sides.

Reassemble the Output Board and the Oscillator Board.

Replace the top/rear covers and side covers.

Install in a TM 5000 series power supply. Apply power.

Analysis;
With the output resistance much higher than specified, the output
level with a load was too low. With a proper output resistance the
output level in a load is now as per specifications.

Hope this helps someone.

Regards

Daniel from Ville Saint-Laurent, Qc, Canada. D22dufresne ( at ) yahoo
( the usual dot ) ca.


HOT Analogue board; Tektronix 2432

Mark
 

Hi All,


Thanks for letting me join TekScopes.

As I look around I see some familiar faces from other groups.

Hello everyone!


I have a problem with a recent acquisition from the big auction.

It is a TeK 2432.

It attracted my attention due to the fact it has GPIB.

Self Cal fails with 'hardware problem - see service manual'

It is failing self tests 7000, 8000 and 9000.

If its any help, CH2 7100 tests fail under self CAL but CH2 passes
under Self Diag.

Please see below for test result detail.

I managed to get a manual (another story) and went through the
diagnostic tree.

The clocks look good.

I did notice the TP231 in 0V, but 1.2V is present on pin 1 of the
clock switching resister packs.

I may have I got the wrong TP.

The TP I think is TP231 is placed away from the parts of the board
that use 1.2V. The one I checked is up by the PSU connector.

The only other odd thing is, everything on the analogue board gets
hot, like very hot, some chips such as the CCD are too hot to touch.

That's everything from transistor to IC is warm or hot to touch.

I have checked for abnormalities in the PSU, everything looks great.

The voltages are spot on with no ripple.

One of the outputs of the PSU is the mains trig with a lovely 50Hz
sine-wave which did give me a fright when I was looking for ripple!

Could it be some sort of high frequency oscillation on the Power
supply?

Or is this just a hot scope?

Is is likely both CCD are cactus or is it more likely its the clock
generator before the CCD?

If anyone wants to do some fault finding on this scope remotely with
me, I am all ears and eyes (and fingers)..


Best regards,

Mark
VK2HMC

Fail Tests:
7111 /CCD/CENTER/NORM-SP/CH1
7112 /CCD/CENTER/NORM-SP/CH2 PASS under self test
but FAIL under Self Cal.
7131 /CCD/CENTER/ENV-SP-SLOW/CH1
7132 /CCD/CENTER/ENV-SP-SLOW/CH2 PASS under self test but FAIL
under Self Cal.

7211 /CCD/GAIN/SHORT-PIPE/CH1-1
7212 /CCD/GAIN/SHORT-PIPE/CH1-3
7213 /CCD/GAIN/SHORT-PIPE/CH2-1
7214 /CCD/GAIN/SHORT-PIPE/CH2-3

7221 /CCD/GAIN/FISO-SLOW/CH1-1
7222 /CCD/GAIN/FISO-SLOW/CH1-3
7223 /CCD/GAIN/FISO-SLOW/CH2-1
7224 /CCD/GAIN/FISO-SLOW/CH2-3

7231 /CCD/GAIN/FISO-FAST/CH1-1
7232 /CCD/GAIN/FISO-FAST/CH1-3
7233 /CCD/GAIN/FISO-FAST/CH2-1
7234 /CCD/GAIN/FISO-FAST/CH2-3

7420 /CCD/PD-OFFSET/CH1-3
7440 /CCD/PD-OFFSET/CH2-3

8121 /PA/OFFSET/NORM-FISO/CH1
8122 /PA/OFFSET/NORM-FISO/CH2

8141 /PA/OFFSET/ENV-FISO-SLOW/CH1
8142 /PA/OFFSET/ENV-FISO-SLOW/CH2

8210 /PA/POS-GAIN/CH1
8220 /PA/POS-GAIN/CH2

8411 /PA/GAIN/50MV/CH1
8412 /PA/GAIN/50MV/CH2
8421 /PA/GAIN/20MV/CH1
8422 /PA/GAIN/20MV/CH2
8431 /PA/GAIN/10MV/CH1
8432 /PA/GAIN/10MV/CH2
8441 /PA/GAIN/5MV/CH1
8442 /PA/GAIN/5MV/CH2
8451 /PA/GAIN/2MV/CH1
8452 /PA/GAIN/2MV/CH2

8511 /PA/INV-GAIN/50MV/CH1
8512 /PA/INV-GAIN/50MV/CH2
8521 /PA/INV-GAIN/20MV/CH1
8522 /PA/INV-GAIN/20MV/CH2
8531 /PA/INV-GAIN/10MV/CH1
8532 /PA/INV-GAIN/10MV/CH2
Hmm 8541 and 8542 pass...
8551 /PA/INV-GAIN/2MV/CH1
8552 /PA/INV-GAIN/2MV/CH2

8620 /PA/VAR-MAX/CH2

8711 /PA/ATTEN-GAIN*/CH1/X1
8712 /PA/ATTEN-GAIN*/CH1/X10
8713 /PA/ATTEN-GAIN*/CH1/X100

8721 /PA/ATTEN-GAIN*/CH2/X1
8722 /PA/ATTEN-GAIN*/CH2/X10
8723 /PA/ATTEN-GAIN*/CH2/X100

9211 /TRIGS/GAIN/A-TRIG/CH1
9212 /TRIGS/GAIN/A-TRIG/CH2

9221 /TRIGS/GAIN/B-TRIG/CH1
9222 /TRIGS/GAIN/B-TRIG/CH2


tek 5304 scope with wide bar trace

 

hello, group!

oscilloscope: tek 5304
display unit: D40
horizontal unit: 5B40
vertical units: 5A38 (i have two)

settings on the horiz unit are 0.1 sec/div and auto trig on.
everything else is off. settings on the vertical units (either unit
installed in either slot or both installed or both removed) do not
vary the results.

i get a vertical bar (instead of a nice dot) that spans from the top
of the display to the bottom and about 2 divisions wide that travels
across the display in about 1 second. intensity dial on display unit
has to be turned way up to see the bar. as i turn the sec/div up bar
speed slows down, and as sec/div decreases, bar speeds up.

if i pull the horiz unit (and the vert units), i get the same bar
about 2 divisions wide and from top of display to bottom, but it
doesn't move. i get the same result if i install on a vertical unit
(either unit in either slot).

i have the manual for the 5403 and the 5B40, but not the D40 nor the
5A38. the 5441 manual seems to have the schematics for the D41
display, which appears very similar to the D40. i used these
schematics and tek's scope troubleshooting guide to "common mode" the
amp stages on the vertical amp board and saw no changes to the
display. i have verified the power board's voltages per the 5304
manual.

right before i got the bar, the scope started repeating and phase
shifting the channel 1 trace that i was measuring. very quickly after
that i got the bar.

any help would be greatly appreciated, even if it's just pointing me
in the direction of the correct section to troubleshoot. thanks, and
sorry for the long post. -chris


549 Manual Ugly and Almost Free

bobkrassa
 

I have an ugly but original manual for the Type 549 Storage
Oscilloscope that I will send for $5.00 to the first person who tells
me they want it. The $5 includes shipping by media mail. It is ugly
because the lower third looks like it got wet - before I acquired it,
and the pages are a gray color on the lower one third. But they are
not sticking. The reason I thought someone might want it is the
pictures are much more readable than in the one on BAMA and the blue on
the schematics shows up fine. So if you are working on one, you might
find it useful, if you are a collector you do not want this. If no one
wants it I will toss it. Please reply off list.


Re: old fashioned 535 - first start after 35 years

Bill R
 

Hi, Michael:

The aluminum chassis in Tek scopes has been Alodized or Anodized (I
can't remember which process is used). This process cleans the surface
and hardens it. I'm no chemist, but I think part of that process uses
potash. If you use potash to clean it I think your chassis surface will
be changed (will not look good).

Any chem heads correct me please.

Bill Roberts

michael.petereit@... wrote:

Dave,

I fond that thread but it didn't gave that conclusion.
I used alcohol for slight mud, this scope was placed in a dirty an humid cellar for years without it's coverage.

The aluminium is best cleaned by caustic potash but it will eat up tin too.
Thus I tried with a industrial cleaner which worked pretty good. In the area of the high voltage transformator I didn't used anything else than alcohol. I was afraid of getting shorts by using chemical stuff.

I try to build up ths voltage divider to measure the high voltage.

BR,
Michael
-------- Original-Nachricht --------
Datum: Sun, 04 Feb 2007 14:27:26 -0600
Von: Artek Media <manuals@...>
An: Michael Petereit <michael.petereit@...>, TekScopes@...
CC:
Betreff: Re: [Tekscopes] old fashioned 535 - first start after 35 years


Michael

For starters , do a search in the Tekscopes archives for a a long
email thread on washing and baking old scopes to get the grime out .
It may be as far back as two years ago but there was a lot of discussion.

Next I would carefully remove and mark the locations of all the
tubes, find a friend with a tube tester and test all the tubes ...

Once you have a clean dry scope and a good set of tubes time to start
tracing the circuits for bad electrolytic.. Many will suggest that
you just replace them all :-)

Does the filament on the CRT glow ? If that is dead ...you may be out
of business till you find a doaner scope

Good luck and HAVE FUN

Dave


At 02:02 PM 2/4/2007, Michael Petereit wrote:

Hi,

now I finished the repair of this pretty old scope. I switched on and
was afraid of getting "flames" out of it.
This didn't happen but even after 10 minutes running no beam appeared on
the tube.
Since the servicemanual describe resistors and capacitors with it's
number within the system the reality looks different.

I cannot measure neither 9kv voltage nor I can find the correct part
cause the scope is pretty dirty inside.

Any hints where to look first ?


Thanks,
Michael



Yahoo! Groups Links



Dave & Lynn Henderson
ArtekMedia
Digitally remastered "out of print" test equipment manuals
www.ArtekMedia.com
manuals@...
952-807-5484




Re: 500 series extender cable

Bill R
 

Hi, Dave:

The vertical signal connections are where the coax is used, plus two more for the "flipped version (580). Before the 580, they were not coax. For the rest of the connections, you can check any 540 or 580 scope schematic for the pinouts.

I have a description in a Calibration Fixtures book that I can scan that page and send you (does not include schematic). The part number for the "Fits All" version extender is: 013-055-00. Contact me off list at bill1904 at comcast dot net.

BR Bill Roberts

componenx wrote:

I've searched the archives a few times, but I haven't found a really good description of the 500 series scope extension cable. Based on what I did find (and looking at my MFs and PIs), the 93 ohm coax should be used for the signals (pins 1 and 3), with gnd connections on both ends. The "HV" lines (9-12)should be generic coax with single-
ended grounds, and everything else can be straight thru single wire. Is this correct? Would it be better to use the single ended coax on all the other lines to reduce interferance? Is there a schematic or description of a "real" Tek extender cable anywhere?
I know that 16 point to point wires will do in a pinch, but since I have the time and RG62 cable, I might as well do it right.
I saw a few posts noting that RG62 is hard to find, but I have local stock of a few different types @ .50/foot
-Dave



Yahoo! Groups Links






Re: old fashioned 535 - first start after 35 years

Stan and Patricia Griffiths
 

Hi Michel,

The only part that I know of in that scope that can be damaged by water is
the power transformer and then usually only if you submerge it in water or
use water with a lot of metal ions in it. You could always remove the power
transformer to keep it away from the water and wash the rest of the scope
with detergent and water. Warm water works best.

I have never heard of using caustic potash to clean a scope so I am not sure
how this will work. I would not do it.

Stan

-----Original Message-----
From: Michael Petereit [mailto:Michael.Petereit@...]
Sent: Friday, February 09, 2007 9:05 AM
To: Stan and Patricia Griffiths
Subject: Re: [TekScopes] Re: old fashioned 535 - first start after 35 years

Hi Stan,

well, I had really doubts thinking about changing the capacitor of this
scope. The one I bought from you seems working fine. There are a lot
more capacitor rolled in paper and with no printed value on it.
In general it's pretty hard to find any resistor or capacitor on the
scope accord to the schematics. There is no part definition printed like
on modern pcbs.
And the dirt covers really everything, especially the wiring with it's
colour scheme.
Maybe it's best first to clean this device but all post from the past
concerning this issue are not really usefull. From outting it into the
dishwasher to placing it into the bath tube and showering it... Hmmm,
it don't want to try this.
The easiest way to get rid of this dirt is caustic potash. It nags the
aluminium and the dirt very good. But without unmounting nearly every
part the cleaning won't be succesful.
I thought about changing all electircal part except of tubes and coils
and special parts at all. What do you thin about that ?

Regards,
Michael


Re: old fashioned 535 - first start after 35 years

Stan and Patricia Griffiths
 

Hi Michael,

The black capacitors I am talking about are located in the -150, +100, +225,
+350, and +500 power supplies and not in the high voltage area. You should
be able to remove and replace these capacitors without removing any other
parts. If one of the precision resistors in the power supply gets damaged,
I have some spares from scrapped old scopes.

Stan

-----Original Message-----
From: Michael Petereit [mailto:Michael.Petereit@...]
Sent: Friday, February 09, 2007 8:57 AM
To: Stan and Patricia Griffiths
Subject: Re: [TekScopes] Re: old fashioned 535 - first start after 35 years

Hi Stan,

the plugin is available and installed. Unfortunately one channel will
not work for sure since the wire of one coil is broken....
But this won't prevent the startup of the complete "vehicle".

For checking the black old capacitors I have to unsold all other
resistors above. For cleaning purpose this is the best choice but a
little bit risky too.

Thanks,
Michael

Stan and Patricia Griffiths said the following on 09.02.2007 08:00:
Hi Michael,

Something I forgot to mention that you may not know is that for the power
supplies in a 535 to work, it MUST have a plugin installed, otherwise, the
load on the power supplies will be too light and they will not regulate.

Stan





Re: 500 series extender cable

Craig Sawyers
 

I've searched the archives a few times, but I haven't found a really
good description of the 500 series scope extension cable. Based on
what I did find (and looking at my MFs and PIs), the 93 ohm coax
should be used for the signals (pins 1 and 3), with gnd
connections on
both ends.
Well, I have just taken a cover off my 012-038 500-series flexible extender,
and the cable is just 16-core plain wire. No coaxes in there at all. BUT
it is a good job I took the cover off, since there are two broken solder
joints in there with the wires just flapping. Cable length is 2 feet.

The rigid extender (013-0055-00) is different entirely. There are coaxes on
8, 9, 11, 14 and 16. All shields are linked and connected to pin 2. Also,
the shields are connected via 0.001u ceramic disc (Z5U) to pin 10. This
arrangement of shield connection is at both connectors. All other pins
(including 2 and 10) are connected with lengths of wire. The distance
between the connectors is 6".

Craig


500 series extender cable

componenx
 

I've searched the archives a few times, but I haven't found a really
good description of the 500 series scope extension cable. Based on
what I did find (and looking at my MFs and PIs), the 93 ohm coax
should be used for the signals (pins 1 and 3), with gnd connections on
both ends. The "HV" lines (9-12)should be generic coax with single-
ended grounds, and everything else can be straight thru single wire.
Is this correct? Would it be better to use the single ended coax on
all the other lines to reduce interferance? Is there a schematic or
description of a "real" Tek extender cable anywhere?

I know that 16 point to point wires will do in a pinch, but since I
have the time and RG62 cable, I might as well do it right.

I saw a few posts noting that RG62 is hard to find, but I have local
stock of a few different types @ .50/foot

-Dave


Attenuator Parts for SC504?

Howard Ashcraft
 

I have a fully functional SC504--except for the channel 2 attenuator.
The SC504 attenuator has a cam that causes individual contacts to be
pushed into contact with plugin boards containing the attenuator
resistors. The contacts are mounted on green elastic bands that are
attached to plastic carriers, three bands to a carrier. In my case,
the gold plated contacts became unglued because someone in the distant
past sprayed some solvent/contact cleaner into the assembly. Because
some of the contacts were stuck to an attenuator board, it is possible
that the board was damaged, too. Although I have been able to make
replacement contacts that have greatly improved the situation, it
still isn't correct.

So, if someone has a junk SC504, I would like to get the contacts and
the carriers and also the 4 plugin boards that are in the attenuator.
I probably can get by with 2 of the contact assemblies, if someone
only has those.

Thanks.