| Manufacturer: | Para-Time Instruments Inc. |
| Model: | 130 |
| Year: | 1967 |
| Schematic: | RE |
| |
| Max. Rate: | > 90 KHz (measured) |
| Display: | dekatron |
| Digits: | 4 |
| Logic: | tube, transistor, RTL |
|
A nice little dekatron-based counter.
This model is notable for it's combination of old and new technologies.
The counters/display are dekatron tubes.
Dual-triode tubes are used for the inter-digit dekatron drivers.
RTL integrated circuits make up the timebase and control logic,
and a few discrete transistors interface between the RTL and the tubes.
Two types of dekatron counter tubes are used.
The first two digits (LSD) use high-speed type 6909 dekatrons,
while the remaining digits use 6802 dekatrons.
The 6802's have the orange glow typical of neon while the 6909's have a purplish-pink glow.
Other than that, their physical appearance and internal construction appear identical.
A tube manual indicates the 6802's are good to 5KHz while 6909's should count up to 100KHz.
This unit seems to count reliably to over 90KHz.
- Unit Log -
| Serial Number: | 0012 |
| Year of Manufacture: | 1967 (Capacitors stamped with 6621, 6708). |
| Date of Receipt: | 1997 Jun |
| State upon Receipt: | Non-functional.
Fair physical condition. |
| Date: | 1997 Jun 30 |
| Procedure: | 2N3877 for reset replaced. |
| Date: | 1997 Jun 30 |
| Procedure: | Neon bulb in gate lamp bad.
Housing opened and terminal strip installed to provide contacts for replacement bulb. |
| Date: | 1997 Jun 30 |
| Procedure: | Input circuit rewired. |
| Date: | 1997 Jul 03 |
| Procedure: | One 6909 dekatron not functional, modifications to bypass the 1st digit (LSD). |
| Date: | 2003 Nov 28 |
| Procedure: | Fuse blown (1A), two 1N4002 diodes in logic power supply (ground side) shorted, all 4 replaced. |
| Date: | 2011 Jul 04 |
| Procedure: | Three 6802 tubes and one 6909 received from defunct Coulter Counter from 1963.
Bypass circuitry undone and 6909 placed in 1st digit.
Unit counts to over 90KHz. |
