Magnum Maverick A24: Review, Conversion, Inside of Circuit Board
Maverick A24 Radio t arrived complete in a very colorful display box. Once I removed the radio from the box, I noticed the meter was a new style with white and red bars.
Magnum Maverick A24
Review of Magnum Maverick A24 Radio
This makes it easier to see the red needle against the white, but the numbers are smaller than the old-style meter. It really isn’t an issue, though, while driving, neither meter is readable.
The front panel looks very nice and is well-marked and laid out. The echo delay control has a center detent for the most popular echo setting.
They did correct the SWR antenna warning light, as mentioned in the August issue. The SWR warning LED has a switch on the rear panel in case you wish to turn it off.
With a 2:1 SWR, the lamp stayed off during a dead key but flashed with the modulation. At 3:1, the LED came on solid.
This is a good feature because your antenna match may be way off on a different band, and this would warn you not to use these frequencies until the antenna system is set to cover that band.
Magnum Maverick Front Photo
Maverick A24 Rear Panel Photo
Although the PC Board has all the trimmers marked, there are a few whose functions aren’t obvious. Below is a list of the trimmer potentiometer adjustments.
Maverick A24 Internal Trimmer Potentiometers
- RV1 – “S” Meter Adjustment
- RV3 – SWR Warning Adjustment
- RV4 – Coarse Squelch Adjustment
- RV5 – FM Deviation Adjustment
- RV7 – TR13 Final Bias Adjustment
- RV9 – RF Meter Adjustment
- RV10 – AM Power Adjustment
- RV11 – TR45 Final Bias Adjustment
- RV12 – TR46 Driver Bias Adjustment
- RV15 – AM Modulation Adjustment
The power on the FM is 40 Watts. The AM low power is 1 watts swinging to 18 Watts peak and is adjustable up to 10 Watts swinging up to 40 Watts peak. The low power setting can be set from 0 to 5 watts internally.
The transmission audio quality is very good, and the adjustable talkback is excellent.
On-air reports were very favorable, and this is with the stock mic. The receiver audio quality is very good as well. The tone is full and clear, even better than the Magnum Delta Force.
The sensitivity is good, too. The audio volume is capable of driving you out of your vehicle with the internal speaker.
The speaker is the same one used in the Delta Force radio. I did encounter a problem with the echo board. The radio tested fine on the dummy load, but once connected to the base antenna, there was a mic key click echo every time the mic was keyed with the echo volume set at mid-level.
There was minor RF feedback on the transmitted signal and in the talkback. This was corrected by the addition of a 390pf capacitor to the echo volume signal to ground on the echo board. This was so minute it may not happen with all or many antennas.
Magnum says they are looking into it, and surely any future radios will have a fix or this fix in them (UPDATE: See Maverick A24 Technical Bulletin in February 2002 issue). Magnum has a resistor change for customers who want to make the echo more like a turbo echo rather than a reverb-type one.
This involves changing R618, a 33K Ohm resistor with a larger value of up to 75K Ohms. To get the sound you want, slightly increase the value until you reach the desired effect. In summary, this is a very good AM/FM 10-meter radio.
It will go head-to-head with the Connex 3300HP and General Lee radios. For the price of a 3300HP, you get a 40 Watt peak radio with antenna warning, adjustable all mode talkback, adjustable power, separate echo ON/Off switch, 40 Watt FM, a florescent replacement front panel, and other conveniences over and above what the other radios offer.
Magnum Maverick A24 Conversion
The conversion is very simple and is the same as the Connex 3300, General Lee, and other similar 10-meter radios. Just remove the four 100 Ohm resistors on the bottom of the main circuit board in the PLL area. Reference the photo below for the four resistors.
I will cover the adjustment potentiometers when I write an updated review on the Maverick A24 once I get my hands on a production radio. The designators will most likely change on the production unit.
To publish them as they are in this unit would only cause confusion once the production radio is released.
Inside of Of Magnum A24 Main Circuit Board
The photo to the left shows the basic layout of the Magnum A24 main circuit board. The Alpha Force-type echo/talk-back circuits have been moved to a separate PC board.
In the middle photo, notice there are no additional engineering change components tacked to the bottom of the PC board.
It’s pretty remarkable for a pre-production radio. To the left, you will notice the speaker. This is the same speaker used in the Magnum Delta Force radio.
If you’ve heard the Delta Force, you’ll understand the importance of the speaker. There are only two to three external speakers that improve upon the sound of the Delta Force internal speaker.
Magnum Maverick A24 Echo Circuit Clock Noise
This modification will eliminate any clock noise or transmit oscillation that may occur while using the echo circuit in the Maverick A24 transceiver.
- Disconnect the transceiver from the power source.
- Remove the speaker side cabinet.
- Unscrew the echo board from the side chassis of the transceiver.
- Locate Q602 on the echo board -Q601 is an empty location on the echo board; there is no component.
- Install a 47,000pf Monolithic Ceramic capacitor at Q602, as illustrated below.
In addition to this tech bulletin, Magnum notes that there have been some A24s that have been found with a 1K resistor in the R77 location. This resistor value should be 2.2K.
This is located in the receiver IF stage and the 1K causes the receiver to be far too sensitive and noisy. It’s a good idea to check for this in all radios, as well as those that exhibit this symptom.