Tag: Electronics Restoration
Analysis of Sprague 672D Capacitor Failures in vintage HP Test Equipment
28th November
Shaun Merrigan investigated Sprague 672D Electrolytic capacitor failures in the HP 70000 MMS test equipment. He found that due to thousands of hours of running time and high internal temperatures, many capacitors have failed. The capacitors made before 1990 are highly prone to failure, while those made between 1990-1999 show signs of aging. He replaced the faulty capacitors with Chemi-Con KYA and KZN series capacitors and all modules are now functioning properly.
HP 70100A Power Meter Rubber Pad Replacement
24th November
The Hewlett Packard 70100A is the power meter module in the HP 70000 modular test system. This post will document a problem common to three 70100A units I have recently restored.
As part of the restoration process, I opened the modules to perform a visual inspection. What I found under the outer cover was this:
70100A PS CPU Board Solder Side Overview before repair
HP 70100A PS CPU Board Deteriorated Rubber Pads
HP 70100A PS CPU Board Deteriorated Rubber Pads
HP 70100A PS CPU Board Deteriorated Rubber Pads
HP 70100A PS CPU Board Deteriorated Rubber Pads
The rubber spacer pads between the circuit boards and the outer metal cover had deteriorated to the point of liquifying and running down board via gravity. All the pads in the three units I examined were afflicted to some degree. Several years ago, I documented a similar phenomenon … Read More »
Tektronix Type 106 Square Wave Generator Refresh
20th June
Introduced in 1966, the Tektronix 106 Square Wave Generator is a signal generator which can produce fast rise (<1nS @50 ohm loads positive or negative going) or high amplitude (120 Volts, high impedance load) square waves from 10Hz to 1MHz. It is used for oscilloscope calibration, risetime testing and for triggering extremely fast rise (<100pS) tunnel diode pulsers. The 106 uses a combination of vacuum tube and discrete solid-state technology. This is the sort of equipment that was used for development and testing during the NASA Apollo Program through the 1960’s.
The cost of the Tektronix Type 106 was USD 590 in 1966 or about USD 4900 in 2021 dollars. I was fortunate enough to obtain one of these units in decent condition and I was able to restore it to better than factory specification. What … Read More »
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 »