some questions about D5, R32, analog part, battery and other

[Sergey7084]

Hello,

Dear Friends, here is my short history and my questions.

It is my old hobby from school but a while last many years I have few really time for this. Few hours ago i had completed of my DSO068 kit successfully (I hope). I had only test of source voltage and shorting of JP4 (and JP1 for now because i will add battery later). The R32 may be i will correct R2 of chargers later. Also i had added of diode D5 for future but I not shorting JP5 for now. Also I replaced Y1 20MHz to another with internal capacitors (for more stability). RF analog parts are not testing now.

After this i pressed power ON device and get working menu and keypad.

Initially I had of next firmwares and PCB:
PCB: 109-06800-00H
Bootloader: 113-06803-020
Main: 113-06801-060
Keypad: 113-06802-030
Also I have BOB1-BOB5 installed.

After some time (turn of encoder, press of some keys for study) I receive abnormal screen and reset also on/off are not correcting of this situation. After some on/off and press keys the DSO068 are rebooted normally. I had downloading of 113-06801-061 (main) and 113-06803-020 (keypad) successfully (Win7 x64, by avrupd.exe). The bootloader are not changed (I known what it is very serious and may be give some global problems if unsuccessfully). After these actions the DSO068 are working (i’m repeat – I’m not tested of RF analog part now). Displayed versions are not changed but I had reading here what it is normally.

Also I successfully connected my DSO068 to JYELab v.070 but I had not use one in really situation, I had only connect and try change of few parameters for test connection.

At now I have observe of only one not good nuance. PCB has only four screws for mounting around and not has any supports in center. For this reason when user will press of on/off, buttons and turn switches – the PCB will have distortion and after little time may be damaged of soldering and PCBs patches. For this reason I will install of 2-3 round cylinders exactly between PCB and back cover for protect PCB distortion. It is important.

At now I have some questions. Help me please if possible and if not difficult.

1. I understand what add of D5 is required for use with battery. I’m right or not?

2. I understand what battery are need 3.7V. Yes? What battery capacity is recommended for DSO-068? Is it need add of R32 for this recommended capacity and how resistance must be R32 in this case?

3. I soldering wire of M.F.T. connector (RG50 output) to surface two points – please check of my picture (sorry for some soldering paste – it is not complete unit now). I not fully understand about true point for connections because manual what coming with kit and downloaded manual are not 100% compatible with my PCB. Is it true point for M.F.T. connector?

4. What function is of capacitor C3? Which action of C3 (shortly)? If it is need/required for some cases please provide capacity of C3 and recommendations.

5. From kits manual I have very small information about C5 and C8. Is it possible providing of more information about process of tune of these capacitors?

6. I had solder of connectors to some places for IDC connectors – named U4 PGM, U5 PGM, PD5. What is really functions/future of these connectors and what is possible connect to ones (shortly)?

7. I had found what LCD screen is acceptable but not very well. The resistor POT1 is adjusted of contrast/visible but in very small range. Also I not get of really good contrast without light black or dark background. Is it possible of improved of black LCD contrast without bad background? May be need of adjusting of R30?


I hope what answers to my questions will be also usefully to many another people.

Thanks in advance!

Sergey

[jye1]

Hi Sergey, please see my answers below.

1. D5 needs be installed if user wants to use external 5V power supply. Usually this supply shouldn't be battery since it will power the charger BOB2 just like the power from USB connector. In fact D5 was meant to provide a option to use J2 as power supply connector if user don't want to use the USB connector.

D5 should not be installed if external battery is to be used from J2. Instead the jumper JP5 should be closed. For external 3.7V Li-ion battery it can also be charged by BOB2.

2. Battery capacity is not critical. 1000mAh - 3000mAh is good. If battery capacity is large the charging time will be longer due to charge current is limited. For R32 value calculation please see the datasheet of LTC4054 http://www.jyetech.com/Products/095/LTC4054.pdf .

3. You have got an "H" version PCB. The correct schematic is here http://www.jyetech.com/Products/LcdScop ... c_068H.pdf .

4 & 5. C3, C5, and C8 are all for input capacitance compensation. Please see the "Assembly Tips" section in this post http://www.jyetech.com/forum/viewtopic.php?f=19&t=1108 . The post is for DSO Shell. But the theory is the same.

We omitted C3 since it needs to be very small. Because the input capacitance of OpAmp varies small C3 becomes not very effective.

6. J4 and J5 are for programming the micro-controllers. To do this some kind of programmer for AVR series micro-controller is required. It is suggested to search the net with "AVR programmer" to get useful information.

7. This might be an isolated case. If it is found unacceptable please contact JYE Tech for replacement.