The AM Forum

    Customer says he has bad finals in his FT-1000D. It's only making
100 watts.  I ask, "On all Bands?"  His reply: affirmative.

    These things are not really my "Forte", $260 just for the
Zitters... From RF parts.  Really?  Anyway, He shleps this thing
over here and I find the following:

band    power    band    power    band    power

1.81    80            14.1    225        28.1    220
 3.6    125            18.1    225        29.1    220
 7.1    120            21.1    220
 10.1    115          24.6    220

(Surprisingly Heavy for a rice box).

   It has some mods, INRAD filters and audio "enhancements".
Tuner is off,  but it is obvious that something is wrong. I'm
"SWAG"ing  filter board/diode/relay.. I know there are some here
that have extensive experience with these things.. Any Pointers?

TIA

/Dan

How about wild speculation?

Bad bandpass filter in or after the PA? Not switching the right filter in or having two active?

Relays, little transistors, and diode logic controls.

Hey Patrick,


     Yeah, that's the way I'm leaning. Sounds like
it's going to be a PITA..  He's a Pal, I should just
"Walk Away".. Still, can't "Leave anyone behind".

Thanks Man,

73

/Dan

We had one that did 250 watts+ on 20 and all other bands where out of wack. Some low and high.  The owner got inside and turned adjustments. After an alignment it was 200 across the bands.  Maybe someone got inside it.

Good luck.

Big split in power between low and high bands. Is there a 2nd mixer /Osc. Chain in there somewhere that's semi-working or been fooled with?.

Time for another chart. What is the final's current draw on each band? Also take a look at ALC indication across bands. Might yield another clue.

Two bandpass filters at once happens on some ricers. The ones I've seen will draw a lot of current and only make a few watts. Sometimes cycling power will dump a latched bandpass filter that shouldn't be in the circuit.



 

Might try a reset/reboot of all the microprocessors.

Changed filters?

mixer/IF alignment. ??

Thanks everyone for the pointers. 

   I did do the "Factory Default" reset on the thing as Step 1.
The VCC holds steady at 30V, The Ic was pretty low on the
lower bands but didn't log it. Don't recall even checking it
on a working band to get a baseline. I Should have done that!

   It's off the bench now and I need to hear from my cust.
as I am not sure of his relationship with this rig. I am under
the impression that he's checking it out prior to purchase.
I wouldn't care if it just went away.

   I Know someone has been inside due to the filter swap
and he told me TCP adjustments were made. Believe me,
if he chooses to have me look into it further you guys will
be "In the Loop".

73 and thanks again

/Dan

"  someone has been inside "

Sounds like a smelly can 'o worms ahead. Please remember that....

" No good deed goes unpunished. "


klc

Mr. Wilson, "All your screwdriver and alignment tool tips ought to be cut off at the shaft."  ;D
-As mentioned to my dad by a serviceman in the halcyon days of TV.

Think I posted that before but still relevant with software "fixes" included.

The INRAD rx filters have zero to do with the output power on any band in this otherwise analog radio. Plug it into your test power meter, then plug that up to a tested 50ohm dummy load. set drive and rf power to max in cw mode. set the meter switch to swr, and key the radio. (dont key it endlessly at that power, just long enough to get a reading). If the swr meter reads anything high in the bands that are showing lower output, then there is a bad relay, or bad relay driver in the output filtering network.

Had a similar problem with an Alinco rig. They seem to be famous for it. (I can't remember the model.)
Proved to be the switching diodes on a one of the bandpass filters.

Bill

The SWR sense circuit is before the bandpass filters?

Good Morning,

     Got an update on the FT-1000D..  My cust
has procured another one that is stock and
working well so this one is just going Away!

Thanks for all the advice,

73

/Dan

Jezebel, don't give up yet.
you still have half working well.   ;D

Now you get to do the noise blanker mod. The factory setup is quite useless.

Makes one heck of a good AM rig if one enjoys working with surface mount stuff  :-\

No. The protect unit board (F3114101) is after the LPF unit board (F3082101). The swr protect board will respond to a problem in the LPF "IF" the LPF is putting out anything other than an impedance of 50ohms. IOW, just like tuning up a toob rig, if the output imp is 100ohms and the load is 50, theres going to be a reading showing on an swr meter, which is all the protect unit is (A simple transformer coupled swr meter that can control the ALC to affect power rollback when a mismatch is detected).

Bad caps in one of the LPF circuits can be caused by letting the autotuner slowly hunt while the radio is at full power and the swr rollback happens slower than it really should.. The final board in this particular rig will put out a surprising amount of power and it's enough to cook the caps in the LPF circuits. I've had 8 of these radios to date, (I personally consider them to be one of the best solid state radios ever built), and all were purchased cheaply due to Pout problems. I'd say 75% of the time, LPF board issues were the fix. I'm no super tech, but the 1000D is so well designed, it can be diagnosed and fixed by anyone that can read and understand a print, use a scope, and hold a slobbering iron.   

I agree with Jared that the 1000D is one of the best solid state rigs out there.  I got my loaded and excellent condition FT-1000D cheap because of very poor receiver sensitivity.  The problem was a loose AGC line connection on the front end board, a 10 minute diagnose and fix.

Following the instruction manual will result in horrible AM transmit performance and hard keying with clicks on CW.  In both cases you are instructed to use the RF power control (basically ALC adjust) to limit the RF output while increasing the drive control so that the ALC is activated, it works much better with the RF power control set to where ALC is not active and use the RF drive to set the proper output level.

I really like the 1000D receive performance and audio.

So the SWR sense circuit looks at the source impedance. Very interesting. Thanks for the description.

I would say yes, but I don't want to claim to understand the circuit perfectly.  ::)  I do know that if there's something wrong in the LPF, there will be a high swr reading on the radios front panel meter.