ICF 2010

[RADIOFREEISRAEL]

Good response using FM and AM with the ferrite and telescopic ant., but no reaction to external ant. 
The famous FET is new but is a 2Sk152 with no-1 following the ID.
I am buying 2 BF410D's and try, any other suggestions will be appreciated.
I have not tested J301.
Thank you all

Sam

[N0MKC]

I'd check the external antenna jack; it's soldered directly to the circuit board, and has been known to crack the board & associated traces after a lot of use.  What happens when you wrap a wire connected to external antenna around the whip (inductive coupling)?

The suffix to the 2SK152 indicates the quiescent current draw, I think; a higher numbered suffix would draw more current, diminishing battery life a little over the lower number suffix.  Don't know what would be indicated by no suffix, but the only effect would possibly be that the batteries have a little bit shorter run time.

I've tried MPF102 replacement, but the particular one I used was noticeably worse than the 2SK152 - I expect that substitutes would have to be individually tried to determine what would be a suitable replacement, given manufacturing tolerances and variances between individual FETs.  It would be interesting to see the results you get from the BF410D replacements.

From earlier posts, I see you have checked the voltages on Q303 - those will tell whether or not it is good.  A quick & dirty check is to tune across the range 1619.9 KHz to 1620.1 KHZ with the whip collapsed - if you hear a drop in the background noise as you go up, it's likely Q303 is working as it should. (As I understand it, the CPU switches Q303 out above 1620 KHz to avoid overloading the receiver; at what point it switches back in, I don't recall off-hand...)

[RADIOFREEISRAEL]

Thank you for your response and I will keep you informed about the results with the Siemens BF410D's.  I also will check J301, (am ant jack). I am using a wrap around the telescopic antena and it does help.
I got the feeling that the ant jack is feeling the years...
Regretfully there are no replecements that I can find. I have traced the jack's at the Federal Item Identification guide... It is a J4-1C Position XIII in the chart but not been able to find a supplier.

73

Sam

[N0MKC]

Unfortunately, the antenna (and other) jacks are virtually impossible to find, except from a parts radio...  Lots of people have looked, but I've yet to hear of anyone having success.

Inductive coupling to the whip may be your only way to go, then; you might find that you'll want to put a pot or some other sort of attenuation in line to avoid overloading the front end on strong signals, though.

Tom

[KE3WD]

Consider replacing an impossible to find but broken jack with another that has the same electrical specification by removing the original jack and using short wires to "pigtail" thru the hole to the new jack. 


73

[RADIOFREEISRAEL]

I may have good news about obtaining replacements for the J301 jack.
I have the Federal Part ID and its configuration both form the Manual and the List.
If anyone has replaced that jack I would like to ask if it is posible to send me a general mechanical drawing including the jack's body external dimensions, pins locations and separation, etc.  I have performed some measurements but are not good enough because the jack is still in the PCB.
I prefer not to remove the apparently defective old jack before I receive confirmation that I will be able to buy and install a new one.

Thank you all again

Sam
 

[N0MKC]

It may be a bit of a pain, but you might try looking at the circuit board traces... If the board has cracked and broken the traces, the jack may still be good, and a replacement still wouldn't work.  If one of the circuit traces is broken due to a cracked board, you could solder a fine (~26 ga.) wire jumper in to bridge the break..

[RADIOFREEISRAEL]

Thank you for the idea to look for circuit board open traces. I'll do that and other measurements next week.  I did have a previous experience with open traces but on a multi tester. The on-off switch traces cracking open after some 100 uses.
I will report the findings as well as my experiences using the BF-410D as front end RF amp.

Again thank you all

Sam