Thaught id post a little project from last year. I was given a Koden 32Nm radar which inermitently woud blow the main fuse, these things only pull about 6A on 12V. Since it was working perfectly untill it would blow the fuse, i just had to fix it. Eventually found it was the antena rotating motor that was at fault & not avalable. Managed to actualy get a workshop manual for it, removed the motor & found it was a fixed speed motor the size of a Cassete player motor but had a small disk with slots in it, this was for azimuth pulses for sweep rotation info for the TV type display. I removed the motor & pressed the armature off the shaft & shortened the motor body so it was just a double bearing assy. Then shifted the slotted disc further on to the shaft & shifted its optical pickup to match. This left room to fit a counter clockwise Cassete motor into the bottom af the assy.To join the new motor to the old shaft, used a small brass sleeve with 2 small grub screws acessable through holes drilled in the side of the old motor housing. As you can see by the pics it just fitted (the brass sleeve was from an old VCR tape guides that thread the tape around the drum). It was just a matter of ajusting the motor speed for this aplication about 2400Rpm on the motor to give 24RPM on the antenna. Re ass unit & now have a good Radar.

 

More Pics.

 

Hello, I have an md3000 that does not have the trigger signal in J6 / 9, will you have the manual pages that I am missing from 27 to 40? thanks.

 

Hope these are a help? let me know if you want more.

 

Finaly found the pages.

 

More pages.

 

Thanks dede, I'll see if I can find the fault, I think that without the trigger signal the transmitter and receiver do not work.

 

You do have the Azimuth pulse from the Antena motor at the display board? That creates the trigger pulse, No trigger pulse no transmit.

 

It would apear theres diferences in these model radar. The Triger pulse is generated on the power board on mine & not on the CPU board. Heres pictures of the board in question with CRO pictures of the signals. IC4 on P1 is the start of the signal to Q7 & Q8.

 

hi dede, i got the trigger signal.

 

but the in the if out signal I only have noise and the screen does not show anything

 

All the relavent posted circuits & tests are in post 4. Heres a couple of pictures of the transmitter board & the Magnetron current test point TP2. The results of mine are on the posted circuits. Check to see if the magnetron is actualy working. You obviously wont get any IF output if theres no transmitted signal. I am now unable to take any measurements as i have just dismantled my radar as no body seemed interested in a cheap working radar. Theres also a 5W 10 Ohm resistor betwean P9 & P12 on the Tag strip in the anttena, its the Magnetron fillament feed voltage. Should have +7V on P9.

 

A couple more things, The radar needs to be set on 4Nm for the Tune indicator bars to show on the screen. This is a good indication that the reciever is actualy working. Also the HV powersupply in the antenna unit needs to be working obviously for the Transmitter, but it also supplies +35V DC for reciever tuning.

 

[QUOTE = "debe, publicación: 1597140, miembro: 97218"]
Un par de cosas más, el radar debe configurarse en 4 Nm para que las barras indicadoras de Tune se muestren en la pantalla. Esta es una buena indicación de que el receptor está funcionando. Además, la fuente de alimentación de alta tensión en la unidad de antena debe funcionar obviamente para el transmisor, pero también suministra + 35 V CC para la sintonización del receptor.View attachment 229843View attachment 229844View attachment 229845
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Hi dede, is it dangerous to make measurements on the antenna if it is working? I say it because of the radiation.

 

Yes you need to remove the belt from the antenna drive & have the antenna facing away from you. Also be very careful of the wiring to the Magnetron & its drive transformer & the SCR alongside of the transformer. If you are un comfortable working with high voltages, then perhaps give this project away.