Spectrum Analyzer help needed...

I don't think I've come across this manufacturer before.... Cushman?

How old is it and what frequency range? It can't be all that old if its got a microP inside...

If the circuitry/software relies on the stored memory contents that is a bad design, or maybe it just needs to reset the memory contents?

I will ask around the other forums I'm on to see if anyone knows about this model...

John.

Thanks a million, John. I think the battery was just for storing preset freqs and such, not general operation. The battery had shorted, and the system wouldn't run until it had come back up to voltage. Now, however, it seems to have some jibberish stuck in memory. I've had it since about '96, and it's been a great unit until now.

Thanks,

Dave

Ooooo its a nice looking beast here's the spec... still looking for any tech info...

Radio System Analyzer with Tracking Generator

Monitor

• Functions: Frequency error, FM deviation, % AM, Power, SINAD, audio frequency (Lissajou), SSB
• Frequency Range: 0.45 to 999.9999 MHz
• Inputs: 2 BNC connectors: high sensitivity (2 µV) antenna input and a high power input/output for direct connection of transceivers of up to 150W transmitter power
• Sensitivity (Narrow Sensitivity):
  * FM: 2µV (0.6µV typical) for SINAD = 10 dB; Frequency ≥ 2.0 MHz
  * AM: 2µV typical for S/N = 10 dB; Frequency ≥ 10 MHz
• Selectivity/Squelch
  * Selects IF & audio bandwidths
  * Narrow: 22 kHz & 3 kHz
  * Medium: 22 kHz & 36 kHz
  * Wide: 220 kHz & 36 kHz respectively at 3.0 dB points
• Frequency Error Meter
  * Zero centered meter reads error offset from display frequency
  * Ranges: ±1.5, ±5, ±15 kHz
• FM Deviation
  * FM peak deviation read simultaneously on meter and CRT display
  * Ranges, meter and CRT: 1.5, 5 and 15 kHz peak
• AM Modulation
  * % AM modulation read simultaneously on CRT display and calibrated meter
  * Meter Range: 0 to 100%
• Power Meter Range: 1W to 15W, 10W to 150W
• SINAD Meter Range: 0 to 20dB

Audio Synthesizer

• Frequency Modes Gen: 1 Hz to 19,999.9 Hz

Tracking Generator

• Swept frequency output is exactly equal to input frequency of spectrum monitor
• Frequency Range: 10 MHz to 999.9999 MHz
• Sweep Widths: Fixed - 10 kHz, 100 kHz, 1 MHz per div., and 10-1000 MHz range (for cable fault)
• Output Level: 0.1 µV to 300 mV, continuous

Spectrum Monitor

• Frequency Range: 10 to 1000 MHz
• Dynamic Range: +0 to -115 dB
• RF Attenuator: ≥40 dB in 20 dB steps
• Display Range: 70 dB (10 dB/div.) and 8 dB (1 dB/div)
• Scan Widths: Fixed - 10, 100 kHz/div, 1, 10 MHz/div., and 0-1000 MHz

Oscilloscope

• Frequency Range: DC to 500 kHz
• Horizontal Sweep Rate (Calibrated): 10 msec/div, 1 msec/div, 100 µsec/div, 10 µsec/div, ±5%

Signal Generator

• Frequency Range: 0.45 to 999.9999 MHz
• Level - Range: 0.1 µV to 300 mV rms, continuous
• Modulation: FM/AM/CW

General

• Approx. Weight: 44 lbs
• Dimensions: 8 1/4" H x 15" W x 18" D
• Power Sources: 115/230 VAC ± 10%, 50-400 Hz, 90 Watts

Yeah, its been great and would do everything I needed for my repeater maintenance. I'm worried about this recent problem, though.

Dave

Never have seen the device, I try to reason:

If there is a setup of an environment for working, I wonder if it can be saved. That would be done in the memory that you are talking about. In the menu could it be resetting to a default value?

Probably due to the method used for soldering the battery in, you gave it a bundle of opens and closures.....I would expect to find a link near to the battery that removed battery power, try removing it for a few hours before replacing.

Generally, the link should be opened before the replacement of the battery is made (if a link is there at all!).

The only other way to make a reset if there is no link of button for such an operation, is to short the battery out for a few seconds, but I really do not recommend this as it can cause some battery types damage!!! Your choice on this last one with eye protection - just in case!!

Hmmm, I encountered something similar once. A company that supplied medical equipment called me to fix something they called an Infusomat. It was a machine that controlled the flow of fluids injected into a patient through an infusion.

For a seemingly simple job it was microprocessor controlled. Unfortunately, it wasn't working though power was present. I opened it up and was delighted to find a Z80, which I was very familiar with.

Clock was there but the μP didn't seem to be booting up properly. Then I found that the Reset pin was floating! The thing didn't have any provision for resetting the μP during startup. I wondered how many units they'd sold.

I rigged up the circuit below and it worked fine.

I don't know what processor you're using but it might be worth checking for the reset pin. You can find information on the 'net for any processor.

If it has a reset circuit, check if it's working.

I did a search for "Cushman Electronics" on AOL. I did not find a web page for Cushman, but I found references to documentation on Ebay... several people who service their equipment.

You might try searching for them on dexonline.com in San Jose CA. This might get you a telephone number (if the company still exists). If San Jose does not work, try Sunnyvale, Milpitas, Mountain View, or I think you can use the option "include surrounding area". It has been a while since I have done this.

For those who don't recognize Cushman, they are/were THE COMPANY to use for radio service equipment. I first came across them in the early '70s when we used them in testing something really novel... a telephone which fit in a briefcase. Of course that was reallllyyyy another time and another place.

73s de Bill NW7L