Batboard

When you use LAB RSS to both BLANK and INITIALIZE , does the Crystal Reference (8 digit no), Tuning Reference (7 digit number) and Measured Voltage on P1 (9.6v) get carried over ???

All the other alignment data gets carried over but I'm not 100% sure about the "manually extracted" sticker data.

I'm aware that you can use "regular" RSS to INITIALIZE , but I found that LAB RSS version R05.30.00 did contain my required "32 channel, scanning" model numbers - other versions of LAB apparently don't contain all the model versions so you cannot initialize to the version required. Theoretically , using LAB "might" avoid the need to open the radio to extract the data from the stickers but I need 100% confirmation that LAB is using the ACTUAL sticker data rather than DEFAULT values.

Also, anybody know what the Crystal Reference, Tuning Reference and Measured Voltage data are actually used for - is it just for the Ref Osc and TX Output OR does it impact on RX sensitivity?? What is the effect of using slightly wrong values??

Always assume that when you blank a board you must do a full alignment. Proceed at your own risk. It affects transmit more than receive though sensitivity will suffer as you move out of band. You may end up okay, or have low deviation, or have non-linear deviation (especially important for passing data).

Crystal refereance data, tuning data affects the TX and RX of the radio almost like the VCO crossover frequencies do in the Jedi series

This data is used to control the radio's bandsplit, and receiver tuning range, so the receiver will be able to be used across the entire range the radio was designed to cover, and not centered in a small range of nearby frequencies, so you have say, a hot receiver(-130) at 143mHz, but a stone deaf receiver at 157(-87).

This wide tuning range affects the receiver passband, transmit power bandwidth, and can affect deviation levels through the VCO/buffer.
You can also affect the channel spacing with improper crystal reference tuning.

If the reference oscillator is off by +/- 10KC at 16.8 mHz, how far off do you think your receiver and transmitter will be off frequency at 154, or 462?

One tiny error, low on the chain can have dramatic effects during the multiplication process.

Divide errors, summing errors, they all add up to greater errors when you add the effects of multiplication of those errors in your channel data.

You can program the correct frequencies, but the errors will only be visible on a service monitor as you look at the actual signal on the screen, and see the difference in deviation, modulation acceptance bandwidth, and frequency error.

You also affect the IMD rejection, spurious emissions of the radio if the tuning data is not adjusted properly, which can cause harmful adjacent channel interference to other users on nearby frequencies.

Just to be clear, with regard to "Tuning data" , I am refering to the 7 digit "Tuning Reference" number on the sticker inside the Maxtrac, as well as the 8 digit Xtal ref number.

All the other "tuning data" (TX power, dev, ref osc) has been "carried over" by using F3 in LAB RSS when converting from 6 to 32 channels - although I carefully manually recorded all the different values for the 16 different test freqs (just in case)!!!

The closest info I could find on this is the M120/M10 Dealer Service Manual, which is for the GM300 RSS.
That is pretty similar to the Maxtrac.
It stated that the radio must be opened and the tuning info entered in the RSS during the initialization procedure.
My understanding has always been that the crystal tag, the tuning data and the 9.6 volt info had to be entered every time.
The Maxtrac service manual describes the crystal label as the temperature coefficient data, and the 7 digit code as being generated by varying the control voltage to warp the oscillator freq (changing the varactor).
That is monitored at the factory, then written in the radio on a tag, and it is RF board specific.
Today I tried both initializing with the "old tuning data" and entering the crystal/tuning code/9.6 volt info.
What I found is that by monitoring the 14.4 mhz ref osc, when I entered the info manually, the oscillator was closer to the correct freq than when just accepting a previous value.
When the crystal data, tuning code and 9.6 volt is entered, the oscillator immediately changed by tens of hertz.
I appears there can be default values that will work, but the info on the "tags" get you more accurate (stable) results.
Years ago, Monty (RIP) told me the best way was to always blank with LAB, but initialize with regular RSS.
And I have found that to be the most stable method.
But, I always re-align and re-calibrate my radios. (Unless I am just experimenting on the bench).
If someone doesn't have a service monitor to both re-align and re-calibrate, then I think the procedure should be:
Use standard RSS in the service mode, go thru the board replacement procedure and write down the CALIBRATION values at the 16 freqs for TX power and the 16 freqs for TX deviation.
As you leave each "page" to move to the next step, hit F10 instead of F8, to just move to the next step NOT write the data.
Once you have that info, use LAB to blank the board.
Once the board is blank, again use STANDARD RSS to initialize the board for the model you have, using the Board Replacement choice.
When you get to the first page of board replacement, enter the crystal data, tuning code, and 9.6 volts as measured.
When you get to the Tx power calibration page, enter the values you got prior to blanking the board.
Same with the Tx deviation calibration page.
I have used that method MANY times to save time while just experimenting with a radio.
Saves dialing up all those freqs, etc.
I played with a 10 meter Maxtrac most of the day today, and I found entering the data allowed me get the radio to work from 29.000 to 36.000 mhz with the Tx power and Rx sensitivity remaining consistent.
The deviation varied more with greater dev as the freq went lower. But I didn't change the values in the calibration to fix that.
I believe it would work tho.
The TX power calibration worked as it should, and I could keep the power within a couple watts over that range.
I tried three different logic boards, and several models of radio (Max High Sig, Max 300, Max 100, etc)
Best results were with the 16 pin logic board, Max High Signaling, model no surprise there.
Bottom line is that you likely can init with LAB using the "program with old tuning data" but my results were better when entering the crystal/tuning/9.6 volts directly.
As usual, your mileage may vary.

Thanks very much PETNRDX for the very helpful reply.

When I used LAB RSS to both BLANK and INITIALIZE, I noticed that the Maxtrac was TXing about 100Hz high compared to previously- so I think you have confirmed that LAB RSS uses DEFAULT values for the Xtal Ref, Tuning Ref and Measured Voltage rather than the ACTUAL values!!!

Next step now is to use regular RSS and repeat the BOARD REPLACEMENT procedure and use the manually extracted sticker values.

However, if the sticker is missing, I guess using LAB RSS to INITIALIZE provides OK results for ham operation. I wonder if regular RSS, when you don't have the sticker values, also loads default values??

Do you have any views on how best to lower TX output. I just left all the TX Power Calibration values (in the Board Replacement section) as per the original settings (ranging from 111-117) and just lowered the TX Power Adjust in the ALIGNMENT section (NOT Board Replacement section) from 111 to 90 - is this OK?

Any idea what the 29.6MHz sensitivity is for 12dB SINAD - I guess its around 121dBm

I'm still wondering why Motorola didn't just program all low band Maxtracs with 32 channel/scanning capability rather than limit some versions to just 6 channels!!!!!

Any views on the best way to lower TX Power ie. just use "simple" one softpot ALIGNMENT section or "detailed" 16 softpot BOARD REPLACEMENT section?

Thanks

Use "simple" one softpot ALIGNMENT section,

F2 Service
F2 Alignment
Transmitter power