Battery meter inaccurate after backup battery change (X388S)

[wnor]

I changed the lithium backup battery in my JR X388S transmitter per:

http://www.barnyard-buzzards.com/Builders_Corner/Electronics/Transmitter/

Since then the battery meter reads 0.5V low as determined under load with a good-quality digital voltmeter. A fully charged JR 800 mAh battery drops to 9.0 V after two ten-minute flights, per the transmitter's display. However, this "depleted" battery delivers over 800 mAh when cycled with a Litco Alpha 4 (battery is hooked up to the Litco unit for discharge immediately after the second flight - no recharging between flying and discharge). When this problem first appeared I replaced the main NiCd battery with a new JR 800 mAh pack from Ron Lund, but the behavior is unchanged. The backup battery change was easy, and I can't imagine what I messed up. Any ideas? Have you seen this happen?

[BjornH]

Lets see now...

JR X-347 Voltmeter adjustments
1: Get a digital voltmeter.
2: Recharge the transmitter battery.
3: Set the GEAR switch to the rear position.
4: Press and hold the UP and DOWN keys and power on the transmitter, release the UP and DOWN keys.
5: Select the MDL.# RSET menu.
6: Flip the GEAR switch to the front position then press the DATA+ key.
Flip the GEAR switch to the rear position then press the DATA- key.
Repeat this fairly quickly about 3 to 4 times untill there is a BEEP.
If there is no BEEP after 6 completed cycles it failed, start from #3 again.
7: IF there is a BEEP the screen changes to INTL
8: Screen 1 Service menu: INTL
9: Press the UP or DOWN key to scroll thru the different screens.
10: Screen 2 Stick/Pot centering.
11: Screen 3 Trim centering
12: Screen 4 Switch and LCD display test screen.
13: Screen 5 Stick end point calibration.
14: Screen 6 Transmitter voltmeter adjustment :-)
Hook up a digital voltmeter to the transmitter battery and adjust the transmitter voltmeter display with the DATA+ and DATA- keys to read the same or slightly below the digital voltmeter.
15: Screen 7 Enable or disable is the question
Set BATT to NICD
Set ALRM to 9.3v
Set SDIR to ACT
Set SWMX to ACT
Set SMOD to ACT
Set ZERO to 0
Set TYPE to ACT
Set POT8 to YES
16: Screen 8 Clear memory.
17: Press the UP and DOWN keys to leave the service menu, power off the transmitter, done...

[1275mini]

got any info for the latest pcm10?

[wnor]

Wow! Fantastic! Thanks for this information!

On my X-388S under Screen 7 I have these options:

BATT
ALRM
SDIR
SWMX
SMOD
MAX 8 CH (instead of ZERO)
TRNS (instead of TYPE)
POT8
Screen 8 is "TXD *STR" (instead of Clear memory), and there is a Screen 9, "369.8 FF:00"

What do the options in Screen 7 do (I'm really curious)?

Thanks again for this information!

[wnor]

I may live to regret this, but, in an attempt to answer my own question above, I've been trying key combinations in the "hidden memu" of my X-388S. In the key below, the instrucrtion manual's terms are used. "Model Set-up Mode" (MSM) refers to the mode you enter if you hold down the UP and DOWN keys during power-up. "Function Mode" (FM) refers to the mode you enter if you press the UP and DOWN keys after the unit has already been turned on.

SDIR ACT results in display of STK.T NORM in FM. This feature can be set to reverse the direction of travel of both the throttle and collective servos to up-down movement of the left stick. (Why?)

SWMX ACT results in display of MIX SWAS NORM in MSM. Christmas in July! This enables CCPM!

SMOD ACT results in display of STIK MOD.2 in MSM. This feature can be set to select Mode 1 and 2 -style stick assignments

TRNS ACT results in display of TXD.3*STR in MSM. No idea what this is yet. This also appear as Screen 8 (see above).

Screen 9 looks suspiciously like sets of hexidecimal numbers. Perhaps it is a way to read the firmware.

Additions and corrections are welcome! Thanks so much to BjornH for the information!

[pnaeroneer]

I realise that this discussion is 6 months old, but I believe I now have the FULL deal on the X-388S Service Mode. This includes an explanation and full instructions on the item "TRNS". It is an undocumented feature which allows your model settings, trims etc to be transferred from one Tx to another via the trainer cord, either one model at a time, or all eight in one transfer. I own two X-388S Txs, so I was able to work out the procedure.
The JR 347/388/783 series are very similar so the documents I have prepared cover them all. Note that the XP783 has the same internals as the X-388S, but the 8th channel has been inhibited in the software. It can be activated in a few seconds if wanted.
Send me an email direct if you would like this info.
mervmatthews@xtra.co.nz