Tag: Electronics Troubleshooting
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 »
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 »
Tektronix Type 114 Pulse Generator Repair
22nd May
I recently completed repairing/refreshing and calibrating two Tektronix Type 114 Pulse Generators. This is a solid state pulse generator with variable pulse width (100ns – 10ms) and period (1us to 100mS). It can produce pulses of both polarities (-10v to +10v into 50 ohms). It was introduced in 1965. The two examples I obtained were SN 001791 and SN 003460. Initally, both units were produced output, but the waveforms were distorted (rounded square waves) and far out of specification in terms of period, pulse width, and risetime.
Tektronix Type 114 SN 003460 Front Panel
Tektronix Type 114 SN 003460 Overview
Tektronix Type 114 Pulse Generator SN 001791 Front Panel
Visual inspection also revealed damaged components and mechanical damage. A summary of the issues found follows:
Pulse width and period were out of specificationNegative pulses and square waves were … Read More »
BK Precision 879B LCR Meter Repair
3rd January
The BK Precision 879B is a good quality, dual display 40,000 count LCR (inductance, capacitance, resistance) meter with 0.1% basic accuracy. It was first manufactured in 2010 and is still available (2021) for around $420 Cdn. I purchased mine several years ago and find it very convenient and easy to use.
BK Precision 879B
Things I like about the 879B:
Open/short calibration completes very quickly as opposed to the DE 5000Decent quality Kelvin clips and smd tweezers40,000 counts for extra accuracyVery good accuracy when compared to my HP4263ALong battery lifeEasy to use menu system and quick setup
A common problem with these units is the lack of robust input protection. What this means is that if you forget to discharge a sufficiently large capacitor and attempt to test it, you will damage the front end of the meter which will … Read More »
Ebay IC Tester Instructions Update
14th November
Ebay IC Tester Instructions Update: Several years ago I posted the instruction and datasheets that came with the ubiquitous, generic Ebay IC Tester. These can be found here.
This post updates the original datasheet with new information: The datasheet with the tester indicates that 5v is the upper limit for zener diode testing, but recently tomtektest discovered that the unit can test zener diodes up to about 50v reliably. I dug into my parts bins and confirmed his finding using a range of zener diodes up to 48v. This is welcome information as it gives the tester additional usefulness in testing a much larger range of zener diodes.
Thanks for reading.
Shaun Merrigan
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 »