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HP 3764A DIGITAL
TRANSMISSION ANALYSER
I bought this HP 3764A on eBay as faulty and incomplete to strip down for spare parts. The serial prefix is 2322, so a very early unit as it was introduced in 1984. With no options fitted the original cost was $9,630 in 1986.  From later work, it would appear that Option 002 Jitter Generation & Measurement had been fitted at an extra cost of $2,570, a total cost of $12,200.

Front view showing missing top cover and printer
Rear view
The 3764A Digital Transmission Analyser is for analysing the error performance of high speed digital transmission systems. Three versions of the 3764A are produced, each being designed to fulfill different operating requirements. This flexible approach allows the 3764A to provide substantial benefits in a wide range of applications, from design and development to commissioning and maintenance.

•   Standard 3764A - this is a dedicated 140 Mb/s digital transmission analyser with pattern generation, error detection and error analysis capabilities. The error analysis provision includes error performance measurements for testing Integrated Services Digital Networks (ISDN).

•   Multiple frequency version - option 001 instruments provide the standard 3764A's measurement capability at the four main CEPT bit-rates of 2,8,34 and 140 Mb/s. This reduces the number of test sets required in multiple frequency environments.

•   Jitter version - in addition to the standard 3764A's measurement capability option 002 instruments also provide jitter generation and timing jitter measurement at 140 Mb/s. This offers a cost-effective solution to 140 Mb/s testing requirements.


Specifications Summary

Generator Section 
Clocks: internal clock 139.264 MHz; offset clocks + and - 15 ppm; external clock 1 kHz to 170 MHz. Data outputs: CMI format at 139.264 Mb/s; Binary RZ or NRZ from 1 kb/s to 170 Mb/s, ECL levels, 75 ohm unbalanced. Patterns: PRBS 2'''-1; WORD, 1 to 16-bit fully programmable; ALT WORD, two 1 to 8-bit programmable words, crossover rate controlled by external signal; AIS, "all ones" pattern.

Receiver Section
Recovered clock: 139.264 ± 3 Mb/s. Binary clock: 1 kHz to 170 MHz. Data inputs: 75 ohm Terminated mode: Monitor mode; Binary, RZ or NRZ, ECL levels; External Error, ECL levels. Measurements Performed Error performance: % Availability, % ER <= N, % EFS. Errors: Error Ratio, Error Count, Error Seconds, Error Free Seconds.  
 
Options: 001 four internal frequencies; 002 jitter generation and measurement.

Internal Printer
Any combination of analysis parameters can be selected for printing.

[HP Catalog 1984]

Top and bottom views with covers removed
There is some minor damage internally, probably from a previous repair attempt and 3 missing pcb's although they may be for options not fitted. Just for once I won't try and repair this test equipment! It will be stripped down for spares, especially ECL parts, and any unwanted parts will be added to my items For Sale page which may help someone else.


January 2010

All dismantled to assembly level. For details see HP 3764A Parts.


March 2017

After a long wait, finally managed to buy a complete hardback Service Manual on eBay (thanks Hugh).  This includes: Section I General Information; Section II Installation; Section IV Performance Test and Operational Verification; Section V Adjustment Procedure; Section VI Replaceable Parts; Section VII Manual Changes; Section VIII Service.  Section III Operation is not included. All in very good condition. This will help to identify all the parts for spares use.

The Service Manual identified that Option 002 was fitted. This includes assemblies: A6 Jittered Clock Generator; A7 Jitter Modulation Generator; A8 Jitter Amplitude Control; A9 Jitter Measurement and A10 Jitter Demodulator.

The missing assemblies were A2 Power Supply, A10 Jitter Demodulator, A15 Processor and A23 Printer Driver. 


August 2020

Bought another HP 3764A on eBay.  This one is serial prefix 3228, so a much later unit as production finished circa 1994 when the cost was $14,210. This has fitted option 007 Synthesiser Based Through-Data Jitter Modulation for adding jitter to any 139Mbit/s signal (which replaces the internal printer) $7,980 and option J31 which is not listed. A total cost of $22,190.

Downloaded the Operating Manual of July 1989 with 105 pages.

Front view with Option 007 on right hand side
Rear view, different to earlier units
Top views with and without covers
After cleaning up the 3764A and removing the covers, it was obvious that the foam insert in the fan cover had disintergrated and spread itself all over the inside.  Some dismantling and repair work is therefore required. For details see Repair HP 3764A Digital Transmission Analyser.

Bottom view without cover 
November 2020

Now repaired. Working through the Operating Manual and all the checks look ok. This is a comprehensive data generator and measuring receiver. It can generate frequencies from 1kHz to 170MHz in NRZ & RZ mode, as well as CMI data.

The working 3764A at 170MHz
This was an interesting project to work on!

As I have no immediate use for the 3764A it is now FOR SALE.