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| EIP 545B Frenquency counter |
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| Dave Cawley:
That's good then. The final thing is that the power meter will only function on Band 3. Dosn't bother me though. Thanks Dave |
| robots:
I am very sorry to open VERY old thread, but.... I have also bought EIP 545B from israel. 2 units. One was not working, the other blew fuse. First unit repaired itself on way to me - probably just bad connection on the interconnect. Second had transformer shortage. But back on topic. Power meter is not enabled on any of these units and both have that special WB firmware. I put the firmware into Ghidra (there is support for 6805 cpu in git). After day of digging: eeprom offsets: 0 - set to 0x00 to enable power meter option 2 - set to 0x5a to enable DAC option 3 and 4 set to 0x35 and 0x59 for some magic (probably band 4 operation, I have not traced this, not sure what it does) Frequency offsets: As "douardda" found out, the frequency offset is set in firmware right at the beginning, together with resolution. Frequency offset can be disabled by removing the code, led will stay light up. for resolution: This is the code from douardda's blog --- Code: ---6125 LDX #M005D ;8E 00 5D 6128 LDA #$0D ;86 0D 612A STA $01,X ;A7 01 612C LDA #$05 ;86 05 612E STA >M0045 ;B7 00 45 --- End code --- There is however very important function called right after. --- Code: ---6131 JSR Z66FB ;BD 66 FB --- End code --- This function will commit the resolution value to various places, probably for counter chain. I have traced the gpib commands and from there i have found how resolution is set. So to correctly set resolution to full scale, write 0 to it: --- Code: ---612C LDA #$00 ;86 00 612E STA >M0045 ;B7 00 45 6131 JSR Z66FB ;BD 66 FB --- End code --- I still dont have idea what that 0x5d is. If someone wants i can share my ghidra project files. My firmware is newer than douardda's. I have no idea what is newer. I have dumped firmware from both units. Both firmwares are identical, except for EEPROM. Get them here if you want: http://robot.mysteria.cz/eip.zip None of these findings have been verified on real HW yet. |
| robots:
To enable power meter press: TEST 1 0 - to enter test 0 8 0 0 - to read eeprom address 0, on display you should see content of the memory as last 2 digits 0 0 - to write eeprom address 0 to 0 To enter test 10, you need to flip the switch on band 3 converter board. If not you will get ERROR 20. I had to repair my VCO board, which is quite different from the one posted on page 2. My Microwave assembly is -9 REV C, counter build year is 1995. This seems to be very new unit. http://robot.mysteria.cz/IMG_20200210_103629.jpg Problem was burnt resistor R25 - 51.1 ohm - almost in the center of the board. This resistor feeds power and limits current to the VCO. VCO is powered from 12V line. Resistor burned because one ceramic capacitor was shorted to ground (0.8Ohm measured). These ceramic capacitors are marked(!) AA5 which translates to 0.1uF. Quick reverse of this board: bottom left to right: tuning of the VCO, R6+R9 limit current, Diode D2 (marked A0) - reverse protection shotky, capacitor and inductor to filter the signal. D3+D4 are M4A varicaps. Q2 is probably the vco transistor, and Q4 is buffer transistor/amplifier, signal is divided into 3 parts on the "red" resistors. U3 and U6 are signal amplifiers for the big-ass transistor BLU11/SL (2.5W). top left: 5pole low pass filter and U2 (same as U3) MAR-8 MMIC amplifier. U1 is not populated, probably the same transistor, and its the third output from the VCO. Probably for band 4 operation. Replacing the capacitor and resistor with something i had (0805 100nF and 2x100ohm 1206 in parallel) and the vco woked! This brought band 1 and band 2 to life. Problem now is band 3 not being able to lock on frequency. Replacing Gate board from second unit did not help. I will need to dig into the IF part of the microwave unit. |
| robots:
VCO part repair: VCO output (one that goes to band 2 converted) should be about 0-1dBm. If not the U2 is probably faulty. VCO amplifier is 3 stage amplifier: u3 - MAR-8, Q6 - rf bjt, and the big transistor mounted on the body. Enable VCO amp (test 1 0, 1 8 4 3, 3 f(reset)). Output after u3 should be about +7dBm. Output of the BJT transistor should be about +17dBm. If VCO amp is disabled (test 10, 1843, 37) last 2 stages are turned off, and but U3 stays enabled. In my case U3 was faulty. As MAR-8 is very hard to obtain I went for easier to obtain RF amplifier - SPF5043Z. I replaced U3 with U2. This way the VCO amplifier is in the same specs(or similar) as before. And i placed SPF5043z in U2 position. SPF5043Z is bit different: Input voltage is max 5Volt. I placed little LDO in SOT23-5 package on free ground plane. Wired 12volts to input, and output directly into the L7 inductor through 0ohm resistor. R14 (100ohm resistor) was removed. I also had to replace R32 (200ohm resistor) with 50ohm, to get the signal strength a bit higher. At -6dBm output the counter selftest (test 01) would not count 200MHz. Here is picture of repaired VCO output: http://robot.mysteria.cz/IMG-20200220-WA0002.jpeg Mess is just flux residue, ground planes are hard to solder, as they are placed on the aluminum case. I tested the counter to be mostly in specs. -30dBm signal at 6GHz through 1 meter of RG316(~ -2dB) + 2x N to sma (~ -2dB?) ~36dBm sensitivity. Second counter would not lock VCO to correct frequency. It turned out to be MC12013 on the converted control board. These ECL logic circuits are almost unobtainable (china virus stopped postal service) or for very high price (>20eur + s/h). I suggest scrapping from old equipment. I scrapped mine from 14GHz SSPA from the same era. MC13013 with MC10131 form 40/41 dual modulus prescaler. If someone knows some 40/41 dual modulus prescaler which can go up to 550 MHz please let me know. (SP8793 or MC12016 are not good alternative) I hope this will help someone in future :-). |
| robots:
--- Quote from: robots on February 08, 2020, 06:45:32 pm --- eeprom offsets: 0 - set to 0x00 to enable power meter option 2 - set to 0x5a to enable DAC option 3 and 4 set to 0x35 and 0x59 for some magic (probably band 4 operation, I have not traced this, not sure what it does) --- End quote --- eeprom offset 3 (address 0x803) - if value here is 0x35, counter counts to 26.5GHz , if other, 20.5GHz. Could someone confirm this ? i have no >6ghz source. eeprom offset 4 (address 0x804) - if value is 0x59, band 4 is present Main difference between firmware 2060048 and 2060052 i have noticed is the GPIB board detection and gpib_present flag. |
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