Shaun Merrigan's Information Pages


Tag: Vintage Electronics


Tektronix SG5010 Audio Signal Generator Repair

Posted by Shaun Merrigan in Audio, Electronics, Test Equipment. Comments Off on Tektronix SG5010 Audio Signal Generator Repair

14th December

Background

The Tektronix SG5010 is an audio signal generator plug-in for the TM5000 modular test equipment system. It can generate five waveforms: sine wave, square wave, SMPTE/DIN intermodulation test signal, CCIF intermodulation test signal, and sine wave burst. All these signals may be swept in frequency and amplitude. It can generate very low distortion (THD+N < 0.0008%; my own measurements) sine waves from 20Hz-20kHz. It is CPU controlled with selections made via GPIB or front panel keyboard. These characteristics made it very desirable as part of an audio amplifier test lab. These units command a high price: Several working units have recently (Dec 2023) been sold for $USD 1500.

I recently acquired a non-working SG5010 for a good price. This post documents my efforts (ultimately successful) in getting it working.

Tektronix SG5010 Overview

Tektronix SG5010 Front Panel

First … Read More »


Tektronix CG5001 Calibration Generator Repair

Posted by Shaun Merrigan in Electronics, Test Equipment. Comments Off on Tektronix CG5001 Calibration Generator Repair

12th December

The document describes the repair process of a Tektronix CG5001 Calibration Generator. It discusses the errors encountered during the power-up self-test and the components that were found to be faulty. The document also mentions the use of extender cables during the diagnostic and repair process.


Tektronix 284 Pulse Generator Repair

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on Tektronix 284 Pulse Generator Repair

21st November

This post will document my recent repair of a Tektronix 284 Pulse Generator. This device was introduced by Tektronix in 1967. It can produce:

A 50kHz, 200mv fast risetime pulse. Typically, tr < 70 ps

A 100 kHz, 1 MHz, or 10 MHz square wave at 10, 100, or 1000 mV

A 100 MHz or 1 GHz sine wave at 100 mV

The Tektronix 284 can be used to check the risetime of oscilloscopes, (both sampling and real time) amplifiers, transistors, transient responses, and for TDR work. The pulses are generated by a tunnel diode which is a semiconductor device capable of changing states very quickly. Tunnel diodes were invented in the late 1950’s in Japan and widely used in test equipment through the 1970’s. Tektronix used tunnel diodes in “pulsers” like the 284 and many oscilloscopes including the … Read More »


HP 70001A Power Supply Refresh

Posted by Shaun Merrigan in Electronics, Test Equipment, Troubleshooting. Comments Off on HP 70001A Power Supply Refresh

17th November

I have recently begun to restore several pieces of Hewlett Packard 70000 Series MMS (Modular Measurement System) equipment. The basic component of the system is a power and/or display frame which can house various test equipment modules. This post documents my restoration of the HP 70001A Power Supply.

The Hewlett Packard 70000 MMS is a high-performance, modular measurement system for RF, microwave, and Lightwave measurements. The MMS instruments include spectrum analyzers, signal generators, power meters, DMM, digital oscilloscope, counter, and more. The system is assembled by inserting the appropriate modules into a mainframe (which supplies power, cooling, and communication) along with a display.

Historically, the 70000 MMS system was introduced in 1986 and continued to be available through at least 2001 (based on HP/Agilent catalogs). The latest prices (1993) I could find for a couple of representative HP 70000 systems follows (all … Read More »


Vacuum Tube Tester: The Roetest

Posted by Shaun Merrigan in Electronics, Tech, Test Equipment, Vacuum Tubes. Comments Off on Vacuum Tube Tester: The Roetest

17th March

I recently completed the construction of a PC controlled vacuum tester: The Roetest. This is a computer-controlled tube tester which works as follows:

Using the PC software, load the tube data from the extensive database

Verify the tube data and pinout on the screen; the tester configures the pin connections automatically

Run the tests for shorts and filament continuity

Run the required tests

Test the tube at full voltage and current (not a pulse test)

Save the result

Add the tube and test data to inventory

Roetest V10 Front Panel and case

Roetest V10 Main board and plug in boards

Roetest V10 Front Panel

Construction Details:

4600 Solder Joints

600+ Components

20 separate circuit boards

Mechanical work for socket boxes + drilling and tapping heatsink

150+ hours

Using the PC software, load the data for the TUT (Tube under Test). Pinout and base connection information is taken from an extensive database of over 22,000 tube types.

Roetest … Read More »


Tektronix TM5006 Power Frame Refresh

Posted by Shaun Merrigan in Electronics, Restoration, Tech, Test Equipment. Comments Off on Tektronix TM5006 Power Frame Refresh

17th June

The Tektronix TM5006 is a 6-Bay power frame which can host and power either TM5000 or TM500 plug-ins .

Tektronix themselves had about 130 different plug-ins available which comprised power supplies, signal generators, oscilloscopes, multimeters, test oscillators, calibrators, attenuators, filters, logic analyzers, frequency counters, audio analyzers and more. In addition, numerous third parties made plug-ins for the system. The total number of different plug-ins numbered at least 200. The system was introduced in 1972 and was available in some form through at least 1995. The system is remarkably interesting from a technology standpoint because it encompasses the move from discrete transistor circuitry in early equipment, evolving through microprocessor-controlled units in later equipment. The more modern TM5000 equipment also had network interface (GPIB) capability for control and data acquisition.

In terms of cost, a basic … Read More »


Tektronix Type 114 Pulse Generator Update

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on Tektronix Type 114 Pulse Generator Update

16th June

This is an update to my previous post documenting my restoration/repair of two Tektronix Type 114 Pulse Generators. As of this writing I have completed some cosmetic work on the cabinets, front panels and carrying handles of both units. This includes cleaning and painting the cases, cleaning the front panels, knobs, BNC connectors and replacing the missing handle inserts.

Tektronix 114 Handle Insert Bottom Section Missing

Tektronix 114 Handle Insert New Aluminum Base Plates and OEM Example

Tektronix 114 Replacement Inserts and Tolex

Tektronix 114 Replacement Handle Insert and Tolex in place

Tektronix Type 114 Refinished Cabinet and Front Panel

Tektronix 114 Front Panel Cosmetics Completed

I have implemented a Maintenance and Inventory system which includes an equipment label with QR code. The code includes the Equipment Name, Serial Number, Instrument ID Number, and a summary of the latest service work completed on the unit. … Read More »


Hickok 209A VTVM Restoration Part 7

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on Hickok 209A VTVM Restoration Part 7

3rd January

I have completed the electrical restoration of one Hickok 209A VTVM. This included:

Replacing all the paper and electrolytic capacitorsReplacing all the carbon composition resistors (most were out of tolerance)Installing a polarized AC plug, line fuse and proper safety capacitorReplacing the meter movement (original was mechanically damaged)Rebuilding and restoring the battery holderBalancing the bridge tube resistorsGiving the unit a full check on all modes and ranges

With all of the above complete I can declare the unit ready to use. The cabinet still needs to be cleaned and refinished, but that will have to wait until warmer weather arrives and I can work outside.

The results of my testing were very interesting. I used my lab equipment (see below) to check the 209A on all of its ranges and modes (with the exception of the decibel range). … Read More »


RIFA Safety Capacitor Failures

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on RIFA Safety Capacitor Failures

13th November

RIFA Safety Capacitor Failures have been documented by many of us who restore and maintain vintage electronics equipment. One very spectacular failure was caught live here: courtesy Dave Jones of the EEVBLOG. These capacitors were widely used in test equipment manufactured during the late 1980’s through the 1990’s. The consensus is that the capacitors fail because the outer case (presumed to be a type of epoxy) develops cracks which allows moisture to penetrate the body of the capacitor. This leads to internal short circuits which cause the capacitor to fail catastrophically. Because these capacitors are line to ground, they could see line voltage whenever a piece of equipment is plugged in, even when switched off. The crack network can develop to the point where large pieces of the outer case spall off, exposing areas of … Read More »


Hickok 209A VTVM Restoration Part 5

Posted by Shaun Merrigan in Electronics, Restoration, Test Equipment. Comments Off on Hickok 209A VTVM Restoration Part 5

1st January

This the fifth part of an “N” part series documenting my restoration of the Hickok 209A VTVM, SN 1333254. Hickok 209A VTVM Restoration Part 5: Checking the meter movement.

This piece of test gear is all about the large, beautiful meter movement, so I need to determine if this one works properly. What I intend to do is connect the meter to a precision power supply and good ammeter through a current limiting resistor and then determine how the meter responds. The meter is supposed to be a 500uA full scale movement.

Here is the test setup:

Analog Meter Test Instrumentation Setup

A 10kohm limiting resistor is connected in series with the power supply. The power supply is a Tektronix PS5004 and the meter is a Tektronix DM5120.

Full Scale Deflection on the meter was about 497 uA:

Analog … Read More »