FT-1000D Enhanced AM Modifications

by Bill, W3DUQ

These mods will improve both the transmit and receive audio on AM.

FT-1000D capacitor / resistor / transformer changes for all mods done at W3DUQ:

I-F BOARD:

C2123 remove 470pf

AUDIO BOARD:

C3101 remove .01mfd

C3103 change to .01mfd

C3080 remove .0022mfd

C3123 change TO 47mfd

C3133 change TO 47mfd

C3127 change TO 47mfd

C3135 change TO 4.7mfd

C3082 change TO 100mfd

C3135 change TO 10mfd

C3234 change TO 10mfd

R3052 parallel a 2.2k

R3053 parallel a 2.2k

R3055 parallel a 1k

R3056 parallel a 1k

VOX BOARD:

C8311 change TO .22mfd

C8318 change to 220pf

C8319 replace with a jumper

SECOND RECEIVER (SUB):

C6074, C6402, C6084, C6085, C6086 - REMOVE

C6090 change to 10mfd

Add .047mfd across J6008 pins 1-2

SHF AMPLIFIER:

C9613 remove 68pf

C9614 remove 68pf

C9601,C9602 change to 33mfd

I-F FILTER CHANGES:

Change out the original 2.4 kHz filters with Inrad 2.8(actually 3.1) filters #715c and #716.

Remove the 2.0 kHz filters and replace with the 2.4khz removed in the above step.

Remove the 6khz stock small square filter and replace with Collins 10khz #526-8735-010.(be sure to wire in the added 470uhy inductors/2.2k resistors per Collins instructions).

Note: This will give you 10khz receive AND transmit on AM WIDE plus 2.8khz receive in AM NARROW position. You can also use the modified second (sub) receiver for 8khz AM receive, thus giving you three AM receive bandwidth selections. The AM TRANSMIT remains in the Collins 10 kHz filter mode, thus giving you essentially a "brick wall" audio limitation of around 5khz.

JACK MODS:

Rewire ALC phono jack on rear apron to P3003 pin 2,(100khz last i-f for use with a monitor scope)

Rewire PHONE PATCH phono jack on rear apron through a 3.3k resistor to J3007 pin 3.

Bypass the phono input end with a .001mfd.

This becomes the hi-fi external audio chain input and the vox and mike gain controls will work this way.

On the RX antenna phono jack on the rear apron, solder a jumper from the center pin to L1003 top,

located near the rear left edge of the board. This allows the use of an additional external receiver while the 1000D is in receive mode.

Turn S1001 to the "on" position to activate the TX out phono jack to ground the linear

t-r relay coil.

INCREASE AM RECEIVE BANDWIDTH

To increase the overall i-f bandwidth on the FT-1000D from 6 kHz to 10 kHz it is necessary to adjust three of the i-f transformers.

Connect a signal generator (another ricebox will do fine for this) to the antenna input of the FT-1000D. Modulation should be at 4 kHz.

Set both the ft1000d and signal generator to 3.870 MHz. Set Receiver to AM WIDE. You might want to LOCK the vfo on the 1000D for these setup procedures.

Connect the scope to the main receiver audio output either at the speaker or stereo jack on the rear apron.

Adjust T1012 (73 MHz i-f receive) for a peak S meter reading with 4 kHz modulation turned off.

Adjust T1011 and T1013 (73 MHz bandpass filter) for peak oscilloscope (4 kHz on) level.

Note:

You could also use a sweep generator if available for your signal source.

CAPACITOR CHANGES TO IMPROVE RECEIVER VERY LOW END BASS RESPONSE

AF UNIT

C3059, C3087, C3089, C3090, C3100, C3160, C3161, C3163

C3158, C3083, C3081, C3077, C3084, C3231 FROM 1MFD TO 10MFD

C3102 FROM 10MFD TO 33MFD

C3068 FROM 4.7MFD TO 33MFD

Note: For additional mod's including the information on filter changeout and alignment try these sites:

K6JRF

EXTEND TX

NOISE BLANKER

INRAD FILTERS

K3KY - RX Locking for Diversity Reception and More

Rockwell-Collins Tel: 714-641-5315 NO URL

 

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5 June 2005