Here's how to convert
GE Delta radios
for 'frequency agile' use on 10, 6, and 2 meters, or for 440 Mhz.
Some service manual links are included.
Review these instructions before starting. Don't attempt the modification if you don't feel that you can accomplish it satisfactorily or safely. Once the conversion os done, the Delta can be used in vehicles with a negative ground battery.
This conversion is disciplined, but not difficult. Once done, you'll have a 100 watt, high quality FM radio of which you can be proud.
a) General Conversion Information - Schematic
The external M/P replaces the frequency selection functions of the Delta's internal M/P. The leads connecting to the Delta's frequency synthesizer will be 'disconnected'. In turn, the external M/P 'channels' the PLL for receive and transmit operation and manages the CTCSS tones.
Three conversion techniques are described:
Note: Since Delta radios use CMOS technology, follow safe CMOS handling procedures. Use a grounded soldering iron, not a gun.
b) Constructing The Control Head and Interfacing With the Delta Radio
A control head needs to be built - the components are available. A large Radio Shack plastic enclosure can house the P/C board, the keypad, LCD, the volume control (with an OFF / ON switch), a mike jack and a small speaker. When not needed, the control head can be stored out of sight.
The head may be used with several different radios of the same or different frequency if the pin assignment convention is the same. Since the M/P uses flash memory, it's easy to change the radio interface with a few key presses.
c) Powering Considerations
There are two sources of 13.8 VDC power to the Delta. The first is the high current source required to power the transmitter PA stage up to 110 watts. The second is the low current source required by the receiver and common electronics.
The fused low current 12 VDC lead (say, from your car's ignition switch) that runs to pin 19 on P / J-601 can be brought to the control head and activated by a switch on the volume control. This switched 12 VDC source will also be needed for the new M/P board. If this powering technique is used, then no other power leads within P / J-601 or the DB-25 cable are required.
Or, a small remote power relay may be placed in the Delta, permitting the removal of the control head when not in use. Placing a ground on pin 17 of the DB-25 cable will operate the relay and provide power to both the Delta (on J-601, pin 19) and to the Control Head (on pin 3 of the DB-25 cable). These radios draw considerable current on receive and can render a car - whose battery is not charging - incapable of starting in short order.
d) Using the Delta's Internal Squelch Control
You may want to use the Delta's Internal Squelch Control, if it has one. First, check to see if your Delta has an internal squelch control (service manual). The control is R666 and near the front of the Control Board. If present - remove P-605.
If your radio does not have R666, you may add one. Ground one end of a 10K control, and connect the center wiper to pin 3 of J-605. Connect the hot end of the control to J-608, pin 2. It can be epoxied inside the Delta.
e) Steps Common to All Conversion Techniques
This involves removing first the control board from the radio and then the battery and ground connections through which permanent power and ground leads will be routed. There's no need to drill separate holes in the radio. However, if done incorrectly, there could be damage of surface mount components.
Please become familiar with the process:
This approach will provide better maintenance and no drilled holes. (However, one needs to find a cable on eBay or from a dealer. The Connector Repair Kit - 19D900447G8, and a Thumbscrew - 19A705055P1 have since been discontinued).
Open up P-601 and note the pins with wires on them. Most of these (as well as the wiring within the Delta) will be reused. These pins are so marked here. You'll need to move the pins that are not being used to the other locations requiring them and / or have a supply of spare pins from another source.
Since J-601 pins 5, 6 and 14 are grounded within the Delta, they make logical ground connections. Accordingly, connect five (5) DB-25 pins 7, 12, 16, 21, and 22 and the shield wire from the cable together with P601 pins 5, 6 and 14. Cover with heat shrink tubing - the grounding is done.
Referencing this Table, connect the eight (8) DB-25 wires within P601 to the remaining leads connecting to unmodified portions of the Delta, viz:
Ensure that all connections are correct. A test table provides resistance and voltage measurements at each of the DB-25 connector pins.
Make the resistance tests from the chassis to each of the pins in the DB-25 connector. They should all be close. Correct, as needed.
Next, apply power to the Delta by either:
You'll have to build up a control head, and the required components are available. A large Radio Shack plastic enclosure works perfectly as it can house the P/C board, the keypad, LCD, the volume control (with an OFF / ON switch), a mike jack and even a small speaker.
A 'connectorized' control head may be used with several radios of the same or different frequency if the pin assignment convention is the same for each. Since the new M/P uses flash memory, it's easy to change the radio interface. See suggestions on Control Head construction.
Note: You may program channels used in any of these radios into their respective 'banks'. There are 5 banks of 20 channels each.
With the power off, connect the Control Head to the DB-25 cable. If you have the time, double check the end to end connections with your meter. If not, at least verify that the 13 VDC leads are wired properly.
Remove the fuse that connects the heavy red wire to the low current relay. Connect your 13 volt power supply positive lead to the relay feeder connection and the ground to the chassis. This lets you verify the receive and transmit synthesizers (one for each) without turning on the final amplifiers. Your shack's 13 VDC supply probably won't have enough power for the transmitter.
Temporarily connect a 30 gauge wire to J-702 - the VCO test point in the corner of the Delta's Control Board.
Switch on your power supply and turn on the Control Head OFF / ON switch. The LCD will display a frequency.
The Red LOCK LED on the Delta's control board will probably be lighted indicating a PLL out-of-lock condition.
Referring to the Command Manual, scroll down to find your radio's name and then activate it. The external M/P will save this setting in flash memory. The Delta's PLL may or may not lock.RED Lock LED might extinguish. Using a non-metallic screwdriver, adjust the Receive VCO (C220) clockwise for about 3.5 volts on your meter. This sets the low end of the VCO within the recommended range (3.5 - 7.5 volts) for reliable receive operation. The external M/P will select the frequency segment based upon the frequency entered. In my conversion, the Wideband Delta would receives up to168 Mhz, so I can listen to public service broadcasts and the weather channels.
Crucial Note - Place the fuse as close to the car battery as possible. This way, a ground on the power cable running elsewhere in the car (say, under the carpet or near the gas tank) will not burn up your car, or cause even more severe consequences! For Delta's running close to 100 watts, use a 25 to 30 amp fuse. For Delta's set to 45 to 60 watts, use a 15 to 20 amp unit. Don't omit the fuse!
Turn on the radio and select a CTCSS tone frequency.
If you have another radio (like a hand held) with
capability, transmit with the same CTCSS tone selected and verify that
the Tone Detected LED
lights. Transmit with the Delta and set the tone level on the
so that the tone
activates tour hand
held's receiver (when set to break the squelch when the correct CTCSS
tone is received).
n) Hitting the Road
Mount the unit in the trunk of your car (or place it somewhere in your shack), ground the chassis to the car frame, mount your control head in a convenient spot, connect the high power leads to your car battery (again, don't forget the fuse), and you're all set to 'rock and roll'.
Note: Even though this conversion will not affect the Delta's 'spectral purity', the FCC's 'type acceptance' was voided when the radio was modified to accept the frequency agile controller. Therefore, it can never legally be used to transmit on non-amateur frequencies.
Delta Connection Points & Connector Pins
J-601 Pin Used
|For Modified Plug
|M/P Board Pins||
|13.2 VDC||P-601 Connector
(see powering considerations)
|-||26||Clip HL-1 (see text)||3||None||
Switched DC to M/P
|Ground||P-601 Connector||-||5||None||see text||MAIN Pin 9||
|On / Off||P-601 Connector
(see powering considerations)
|-||27||Clip HL-2 (see text)||17||N/A||
Low Power Relay
|SPI - Enab||A-701 (M/P) - Pin 8||2||31||Clip HL-6 (see text)||15||PLL - Pin 1||PLL Enable|
|SPI - Clock||A-701 (M/P) - Pin 10||2||29||Clip HL-4 (see text)||13||PLL - Pin 2||PLL Clock|
|SPI - Data||U - 707 (Inverter) - Pin 5||2||30||Clip HL-5 (see text)||10||PLL - Pin 3||PLL Data|
|Chan Chg||A-701 (M/P) - Pin 33||2||28||Clip HL-3 (see text)||14||Main Pin 6||PLL / Wideband|
|Transmit||P-601 Connector Pin 11||2||11||Reuse Pin 11||1||PLL - Pin 4||
|COR Detect||P-601 Connector - Pin 12||-||12||Reuse Pin 12||5||MAIN - Pin 1||5.1 volt zener|
|Mike High||P-601 Connector - Pin 9||2||9||Reuse Pin 9||9||N/A||
|Speaker||P-601 Connector - Pin 18||-||18||Reuse Pin 18||19||N/A||NO Ground!|
|Speaker||P-601 Connector - Pin 20||-||20||Reuse Pin 20||20||N/A||NO Ground!|
|Vol / Squ High||P-601 Connector - Pin 7||-||7||Reuse Pin 7||25||N/A||
|Vol / Squ Low||P-601 Connector - Pin 6||-||6||Reuse Pin 6||see text||N/A||
|Vol - Center||P-601 Connector - Pin 8||-||8||Reuse Pin 8||4||N/A||
10K to 25K
|Squ - Center||P-601 Connector - Pin 15||-||15||Reuse Pin 15||8||N/A||
10K to 25K
|CTCSS OUT||Connect to Delta J603 - Pin 15||2||33||Clip HL-8 (see text)||18||Tones Pin 1||Transmit CTCSS|
|CTCSS RCV||P-601 Connector - Pin 7||-||7||Reuse Pin 7||2||Tones Pin 2||Receive CTCSS|
|TMT AUD OUT||Delta P-607 - Pin 2||2||34||Clip HL-9 (see text)||23||Tones Pin 4||Proc
|TMT AUD IN||Delta P-607 - Pin 1||2||32||Clip HL-7 (see text)||24||Tones Pin 5||'Raw' Mike Input|
|TMT OVER||A-701 (M/P) - Pin 32 (see text)||2||2||Sever FB-2 Lead on J-601 and Reuse Pin||11||JP10 - Pin 2||Transmit Override|
|LOCK (PLL)||A-701 (M/P) - Pin 1||2||3||Sever FB-3 Lead on J-601 and Reuse Pin||6||JP10 - Pin 1||PLL Lock Ind.|
Pin # Function R to Gnd Volts Comments 1 Delta PTT Inf 6.35 PTT Lead used to Key the Delta Radio 2 CTCSS RCV Inf 0 CTCSS from the Delta to the MX-465 Chip 3 M/P Board Power 1 M (Capacitor)
13 4 Volume Center Inf 4.85 Place P608 (or Strap J603 Pins 12 & 14) 5 COR (CAS) 10K 8.98 Ensure 5.1 Volt Zener Present on M/P Board 6 Lock Inf 3.25 Delta PLL Lock Indicator 7 Ground 0 0 Chassis Ground 8 Squelch Center Inf 0 Place P608 (or Strap J603 Pins 12 & 14) 9 Mike High 1.36K 8.99 Use a Delta / Rangr microphone 10 SPI Data 10.6K 4.85 Serial PLL Data Connection 11 TMT OVER Inf 2.49 Transmit Override (see text) 12 Ground 0 0 Chassis Ground 13 SPI Clock 10.62K 4.85 Serial PLL Clock Connection 14 Channel Change 10.64K 4.85 Enables Wideband / Fast PLL Lock 15 SPI Enable 10.69K 4.85 PLL Enable Connection 16 Ground 0 0 Chassis Ground 17 ON - OFF Switch Inf 13 Activates (Fused) Low Current Relay 18 CTCSS TMT Inf 4.46 CTCSS Lead from MX-465 to Radio 19 Speaker 40K (Capacitor) 6.60 Don't Ground 20 Speaker 40K (Capacitor) 6.84 Don't Ground 21 Ground 0 0 Chassis Ground 22 Ground 0 0 Chassis Ground 23 TX AUD OUT Transmit Audio Out 24 TX AUD IN Transmit Audio In 25 Vol / Squelch High Inf 0 - Shield 'Shields' Cable 1.6 Ohm 0
G.E.and the product names Phoenix, Delta, Rangr are trademarks of Ericsson General Electric Mobile Communications.
DISCLAIMER - - If you follow the steps outlined herein, you do so at your own risk. I cannot, nor will not, be responsible for any possible damage to radio equipment, personal property, to yourself or to others caused by modifications that you may make as a result of your reading this.
The M/P controls TRANSMITTING and receiving on many frequencies, suitable for a wide range of HF, VHF and UHF needs. In the USA, TRANSMIT operation requires a license issued by the FCC for the class of operation intended. Amateur radio licensees must maintain strict control over their equipment, preventing unlicensed operation within or outside of the amateur bands.
Copyright 2010 - K3JLS