VC3165 Frequency Counter schematic

[Bodgerbill]

Hi all,

I have a Frequency Counter VC3165 which has partially failed. It has different modes it operates in controlled by 3 front panel buttons but the buttons no longer work so its stuck on reading frequency in mode 1 (50MHz-2.4GHz). It displays the input signal frequency ok and there is only an Ic2 connection between the main microcontroller and display driver so I figure the main microcontroller in it is working fine and the display driver is also working mostly.

Please see attached schematic...

The display driver it uses is a ZLG7289A chip which appears to be a I2C to 8 common cathode 7 segment display driver and button multiplexor. As the frequency display is working fine, but the buttons are not being read, then I figure the problem is with this chip.

This chip has original markings indicating that it is a PIC16C55 microcontroller that is preprogrammed for a specific application and marketed as a ZLG7289A. I dont' have a programmer for this chip nor the source code to program another.

This Frequency counter seems to be common and has been marketed under different brand names. (I have checked all solder joints etc on the board by the way and do not think the problem is a physical one!)

So I am trying to source a replacment ZLG7289A part for it. I have found Chinese datasheets with original manufacturer information on it and I've tried contacting them but they say "sorry not available". Its also not available from the usual suppliers (RS Components/Element14/Digikey).

So if can anyone help please with sourcing the part I would be very grateful.
Thanks for reading this... Ray

The schematic diagram does not seem to be correct but it is the only one I can find on the Net.
My VC3165 has the "B" input going via a cap to the MB506 chip, not the "A" input.

I seem to have damaged my B input with a bit of static and have ordered a new MB506 I.C.
The A input still works fine.
There are no back to back diodes fitted to the B input on my counter.

 

[Harald Kapp]

@Bodgerbill : What is your question? Why did you hijack an old thread from 2012 (with an intermediate update from 2016)?

 

[Bodgerbill]

Well, I was wondering if anyone had the correct schematic.
Sorry,I didn't check the date.

 

[HectorPascal]

Hi Bodgerbill,
Did you ever find a readable and "correct" 3165 schematic? The one you posted is just TOO hard to make out!
I'm vaguely thinking about designing an input interface for a GPS disciplined frequency standard.
Thanks
Hector

 

[Sjmmarsh]

I have a VC3165 with the same problem as the original poster on the other thread - it is ‘stuck’ on channel B and the three buttons in the middle don’t do anything. I found this thread to see if anyone has managed to resolve the issue.

Interestingly, only channel b Input seems to work but it is reading signals generated by an antenna tester from 1.8Mhz to 51Mhz (the ranges it covers) despite Channel B claiming to be for 50Mhz to 2.4 GHz.

Any update on what the problem might be would be appreciated.

Steve

 

[Ledir]

Olá pessoal eu tenho um frequencimetro igual a esse, que está com seguinte defeito ele não acende os displayers. Já troquei o microcontrolador AT89C4051 e gravei os dados HEX do Ci que estava no aparelho para este novo e nada. Eu tinha feito um testador de cristal que é alimentado com 9V. E acabei me distraindo e conectei no canal B. E foi de imediato ele parou de funcionar, só acende os leds vermelhos.

 

[davenn]

Olá pessoal eu tenho um frequencimetro igual a esse, que está com seguinte defeito ele não acende os displayers. Já troquei o microcontrolador AT89C4051 e gravei os dados HEX do Ci que estava no aparelho para este novo e nada. Eu tinha feito um testador de cristal que é alimentado com 9V. E acabei me distraindo e conectei no canal B. E foi de imediato ele parou de funcionar, só acende os leds vermelhos.

Please post in english ... use a translator and post the English version