Shaun Merrigan's Information Pages


Category: Oscilloscopes


HP 1340A Display Repair -2

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Test Equipment, Troubleshooting. Comments Off on HP 1340A Display Repair -2

29th December

HP 1340A Display Repair


HP 1340A Display Repair – 1

28th December

I purchased a couple of HP 1340A XYZ Displays which I thought would be useful as troubleshooting aids and as graphical displays of CRT technology (oscilloscope clocks, and the like). Upon receiving them, they both worked, but careful visual inspection showed some potentially serious problems. I will document the repair process here.

HP 1340A Overview

HP 1340A Overview

HP 1340A Overview

HP 1340A Overview

HP 1340A Overview

HP 1340A Rear Panel, High Serial Number

Visual inspection of the units revealed the following problems:

Heat damaged A1R81 (both units)Heat damaged A2R13 (both units)Loose mounting hardware and corroded wiring on A2Q2 (one unit)

Heat Damaged Components

LVPS A2Q2 Damage

Heat Damaged Components

A2Q2 is mounted directly to the case for heatsink purposes. The hardware was loose, therefore the transistor effectively had no heatsink. I suspect that it had been running hot for quite some time because the PVC insulation … Read More »


HP 3562A CRT Replacement

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Test Equipment. Comments Off on HP 3562A CRT Replacement

28th December

Based on my own observations and reading, the CRT in the HP 3562A is a marvelous piece of engineering. However, it literally fatigues over time and at some point the deterioration cannot be compensated for by the range of adjustments. The solution is to replace the ageing CRT display with a modern LCD. It turns out that SimmConn Labs has such a kit:

http://www.simmconnlabs.com/1401/2501.html

Terry at D-Lab Electronics did a good video on how to replace the original CRT with the LCD Kit from NewScope:

https://youtu.be/WKz7GYBON7g

Terry does a great job of documenting the replacement process, so I will focus on the before/after results. I will start with original CRT images, followed by LCD images and by split screen comparison images. Since I also purchased the RGB to VGA adapter cable from SimmConn, I will conclude with an … Read More »


Tektronix CG5001/CG5011 Pulse Rise Time Measurement

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Test Equipment. Comments Off on Tektronix CG5001/CG5011 Pulse Rise Time Measurement

25th September

Tektronix CG5001/CG5011 Pulse Rise Time Measurement

I wanted to measure the rise time of the normal and fast edge pulses in a new acquired Tektronix CG5011 calibration generator.  The equipment line is as follows:

Tektronix TM5006 mainframe

Tektronix CG5011 Calibration Generator

Tektronix CG5001 Calibration Generator

Tektronix/Tegam 015-0611-01 Pulse Head

HP 83480A Communications Analyzer

HP 83483A Electrical Sampling Module (20GHz)

Background:  The original 015-0311-00/01 pulse head was used in combination with the CG551AP and CG5001 calibration generators. The 015-0611-00/01 pulse head is the later version  used on the CG5010 and CG5011 calibration generators.   The primary differences between the later 0611 and earlier 0311 are:

The 0611 has faster edge rise time of <150 ps or < 160 ps for the Tegam version
The 0311 has slower edge rise time  of <200 ps
The 0611 is larger (taller) than the 0311
The 0611 made by Tegam has an SMA output connector
The 611 made by … Read More »


Tektronix 7904A S52 Pulse Response

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Test Equipment. Comments Off on Tektronix 7904A S52 Pulse Response

20th August

Tektronix 7904A S52 Pulse Response

This post documents my investigations into the following vintage electronic gear:

Tektronix 7904A Mainframe (500 MHz Bandwidth)
Tektronix S52 Pulse Head (tr<25ps)
Tektronix S4 Sampling Head (tr < 25ps)
Tektronix 7S12 TDR/Sampler Plug-in

Here is the test setup:

Tektronix 7904A using 7S12 with S52 and S4 heads. 34ps system rise time. She’s working Captain (MS)

 


Tektronix 7854 Waveform Keyboard Rebuild

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Tech. Comments Off on Tektronix 7854 Waveform Keyboard Rebuild

15th August

Tektronix 7854 Waveform Keyboard Rebuild

From the Tek Wiki:

The Tektronix 7854 Waveform Processing Oscilloscope, introduced in 1980, is a 400 MHz combined analog / digital mainframe in the 7000 series that takes two vertical and two horizontal 7000-series plug-ins. In addition to a conventional analog (real time) scope, it contains an equivalent-time sampling 10-bit digitizer and a programmable waveform processor with GPIB interface. The waveform processor can be programmed using a detachable calculator-style keyboard, using postfix operators (“reverse Polish notation” like HP calculators) that operate on entire waveforms, not just individual numbers.

Tek 7854 Mainframe #2 after cleaning

Tek 7854 Mainframe after cleaning

 

It is to the repair of the detachable keyboard that this post is devoted.  I purchased a keyboard for a reasonable price only to find that some keys were intermittent, and some did not work at all.

Opening up the keyboard showed … Read More »


Tektronix DSA602A Digitizing Signal Analyzer

Posted by Shaun Merrigan in Electronics, Oscilloscopes. Comments Off on Tektronix DSA602A Digitizing Signal Analyzer

14th August

Tektronix DSA602A Digitizing Signal Analyzer Part 1

I recently had the opportunity to purchase one of these units, and I am thoroughly enjoying the process of  checking its operation and getting to know how to use it.  This unit is a laboratory grade, very accurate digitizing oscilloscope from about 1990.  From the Tek Wiki entry:

Inputs
3 amplifier bays, up to 12 channels (using 11A34 plug-ins)

Resolution
8 bits; averaging of N acquisitions increases by log2(N) up to 14 bits

Display resolution
50 pixels/Div

Sample rate
DSA601, max 1 GS/s; DSA602, max 2 GS/s (one channel, left plugin)

Record length
512 to 32768 samples

Sweep rate
50 ps/Div  to 100 s/Div

ENOB
7.2 bit up to 10 MHz, 6.3 bit @ 250 MHz, 5.7 bit @ 500 MHz, 4.5 bit @ 1 GHz

Screen
magnetic deflection color computer monitor, 10″ diagonal (130 mm × 168 mm), 552×704 pixels, 22×11 infrared touch-screen grid

Power
90-132 V or 180-250 V, 48-72 Hz, 465 W (DSA601A) / 585 W (DSA602A)

Features

Automated signal measurements (rise, fall, period, frequency, width, delay, phase, duty … Read More »


Tektronix Scope-Mobile Cart Repair Part 3

Posted by Shaun Merrigan in Electronics, Oscilloscopes. Comments Off on Tektronix Scope-Mobile Cart Repair Part 3

7th May

Tektronix Scope-Mobile Cart Repair Part 3

 

Part 1

Part 2 

This is the conclusion to my repair of a Tektronix 202-2 Scope-Mobile Cart.  Recall that the problem was three fractured trunnion mount bosses which rendered the cart useless (and unsafe) under load.  My proposed solution was to place the bosses into compression by putting a 6mm countersunk bolt through the trunnion mount concentric with the existing hole in the boss.  By using appropriate sized washers between the top of the boss and the frame member I ensure that the boss is placed into compression and the frame member is securely clamped.  This avoids the tensile loading which fractured the bosses initially.

 

Trunnion to member closeup with new bolt and washers in place

The holes in the trunnion mount were countersunk to fit the flat head socket bolts:

Countersunk Hole for new bolt

 

Read More »


Tektronix 556 Dual Beam Oscilloscope Testing: Vertical Bandwidth

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Tektronix 556. Comments Off on Tektronix 556 Dual Beam Oscilloscope Testing: Vertical Bandwidth

27th January

Tektronix 556 Dual Beam Oscilloscope Testing: Vertical Bandwidth

I have been doing some basic testing of my Tektronix 556 Dual Beam Oscilloscope, and I have documented some parts of this process.  I have also captured images of the traces, which I will share here.

Test Setup: Tektronix 556, 1A2 plug-in, Timebase A, Tektronix SG 503 Generator, and Tektronix TG 501 Time Mark Generator

I found the -3db vertical bandwidth of the 1a2/556 to be 65 Mhz, which is to be expected for the 50 Mhz rated 1A2.

 

TM 500 Module with Plug ins

TM 500 Module

50 kHz Reference Signal 6v peak to peak

Tek 556 with 1A2 Vertical 50 KHz BW Test

5 MHz Sine Wave 6v peak to peak

Tek 556 with 1A2 Vertical 5 MHz BW Test

20 MHz Sine Wave 6v peak to peak

Tek 556 with 1A2 Vertical 20 … Read More »


Tektronix 556 Fan Motor Repair Part 2

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Tektronix 556. Comments Off on Tektronix 556 Fan Motor Repair Part 2

22nd January

Tektronix 556 Fan Motor Repair Part 2

In this continuation of Tektronix 556 Fan Motor Repair Part 1, I have removed the motor and mount assembly and disassembled it.  Now I need to figure out the problem and rebuild the motor.

Tektronix 556 Fan Motor Overview, mounted in place

556 Fan Motor Rear

Tektronix 556 Fan Motor removed from mounts.  The Tektronix part number is 147-0029-00.

 

Tektronix 556 Fan Motor

Tektronix 556 Fan Motor removed from mounts.

Tektronix 556 Fan Motor

Tektronix 556 Fan Motor removed from mounts.

Tektronix 556 Fan Motor

The next few images show the disassembled parts of the motor:

Rotor, end bells and bushing assembly

556 Bushing Assemblies and Rotor

End bell inside, retainer, spring washer felt and bushing.

556 Fan Motor Bushing Assembly

End bell and bushing assembly

556 Bushing Assembly

Rotor and spacers

556 Fan Motor Shaft … Read More »