Amstrad DRX100 UHF Tuner I/F output pin

[david miles]

I have just bought a "faulty" Amstrad DRX100, hoping to use the UHF tuner to increase the bandwidth of my homebrew spectrum analyser. I am having some trouble identifying the I/F output pin ( 13 pins ) Could any technical person help me identify it?

David Miles

 

[Topper]

:-Welcome1 to the forum david miles,
Have you done a google search for this? it is a rather specialist request I can only wish you good luck as whilst some members do repairs down to component level they may not have come across a requirement to know the answer to your question.

 

[Llew]

I have just bought a "faulty" Amstrad DRX100, hoping to use the UHF tuner to increase the bandwidth of my homebrew spectrum analyser. I am having some trouble identifying the I/F output pin ( 13 pins ) Could any technical person help me identify it?

David Miles

Don't think it's as easy as that. I think A/D conversion is done in the tuner itself, so no IF output is available on the pins.

Anyway, you can d/load a circuit diagram from here. Looking at the tuner, it just shows SDA/SDL connections, LNB, AGC and voltage inputs -


_www.satcure.net/pdfs/DRX100_service_manual.PDF


Llew

 

[david miles]

Don't think it's as easy as that. I think A/D conversion is done in the tuner itself, so no IF output is available on the pins.

Anyway, you can d/load a circuit diagram from here. Looking at the tuner, it just shows SDA/SDL connections, LNB, AGC and voltage inputs -


_www.satcure.net/pdfs/DRX100_service_manual.PDF


Llew

Thank you Llew for the manual link. Problem:- manual shows tuner having 14 pins, my board has tuner with 13 pins. Any idea why?

David.

 

[Llew]

Can't check now, but maybe showing the LNB input as a pin?

Llew

 

[Llew]

Ho hum... I see your point. Academic though for your project (unless you can find a diagram for the tuner itself, to find the IF section).

If you have the make/version number on the tuner, I suppose you could do a search.

Llew

 

[easysat]

Thank you Llew for the manual link. Problem:- manual shows tuner having 14 pins, my board has tuner with 13 pins. Any idea why?

David.

Maybe the 14th pin is a tab or something (grounded) used to solder the tuner case to the main pcb?

 

[easysat]

I have just bought a "faulty" Amstrad DRX100, hoping to use the UHF tuner to increase the bandwidth of my homebrew spectrum analyser. I am having some trouble identifying the I/F output pin ( 13 pins ) Could any technical person help me identify it?
David Miles

It's a long time since I played with one of these so I'll try and check tomorrow, but from memory the tuner has I and Q baseband outputs. Within the tuner, you should find an IF at 480MHz. Maybe you could connect some coax at this point if you just want to down convert from the 2150MHz - 950MHz to 480MHz?