Skip to main content

Ponyprogging ATMEGA328 U3S

No more 6m signals from Japan  time  to finish some projects

After faulty applying  12V on the QRP-LABS U3S smoke came from the BS170
Display back-light ceased out U3S was dead did not boot the ATMEGA328 was blown.
Placed the working U3S in its case
Applied  power on it but forgot to check the Voltage  major mistake.

The ATMEGA and the BS170 where smoked but no other damage
The  Si5351a Synthesizer board has its own 3V3V regulator that protected it
The QLG1 GPS rx was not yet connected besides its chip has it own 3V3

So i had to program a new  ATMGA328   with U3S V312.hex

The ATMEGA328 was programmed  with an other device verified okay
But it would not boot. I had to use my own ISP Ponyprog and SI-IO interface

Ponyprog V2.08d beta has the ATMEGA328 in the device list
Earlier version not.
With SI-IO to the U3 SPI socket it first failed to see the 328.
2 things where wrong:
1.The U3 Reset needs R3  100k  (91k)   not the jumper to +5
2. Had to remove C1 on CLK. 
Then it could read and write to the 328
Reading the security/configuration bits   only  BODLEVEL0 was checked
un checking this bit and the U3S was booting again

But much lower output level 50mW and the other BS170 already heats up !
No way reaching 500 800mW  like my first U3S does with a cool BS170
It seems every U3S behaves different
Could it be that the BS170 also is counterfeit ?
The circuit is simple not many parts involved the Si5351A drives direct over 100nF the BS170
It is 5V powered over a bifilar wound choke. The output is token over 100nF that's about it.
It is as simple as can be .

Removed the 5W-PA since it never could never bring the 28MHz  power to the wanted 5W level
A mistery to me.
It seems an easy job for  the RD15HVF1  to amplify  500mW to about 5W ??


Popular posts from this blog

SPF5189z Low noise preamp 23cm

14-4-2018 updated

Above the low noise  preamp 50 - 4GHz    ebay  6€

Tested  2 small porto antennas
1 Baofeng UV antenna left   2nd best signal on PI2NOS
2 eBay DIAMONDSRH805S  wide band 144/432/1200  it works for its size as expected
3 piece of wire :   best signal in the setup...

Unit under test at workbench.
It was stable  50mA  at 5V   few days,  but sudden the current went up to 100mA
And i could  no longer adjust it with the negative bias Voltage.
The - Voltage went to zero and the SPF input port became low Z.
This SPF5189z was broken  no oscillations, no input overload just it broke while i was receiving the PI2NOS 430.125 using a small antenna at the workbench.

The specs of  SPF5189z  say it has an internal circuit  regulating the bias current.
Replaced . again   with an other of the 5 spare SPF i have.
The new one again could be adjusted at 50mA  5V 
The current raises to 150mA  when removing the  negative gate voltage.
Where is that internal bias circuit ?
I suspect  eBay …

2011-01-22 DIAMOND X30 2m 70cm 1m30 Colinear inside

Having relative poor signals on the local 70cm / 2m channels using this Diamond collinear 70/2 combi antenna at a height of 25m. I needed to investigate what could be wrong.
Measuring the cable only 3W is left for the antenna of the 10W 435MHz output from a IC451E
The cable is 30m type H100 Z50 10mm outside diameter it is semi air-spaced but has an impossible 4mm² solid CU inner conductor not much air left. I preferred the H43 Z75 cable having lower loss and mechanical better ratio in conductor size but it is no longer selling i think. This H43
3W should be enough for a comfortable noise free FM signal. But only 27km away at PA0A the signal is weak too weak something must be wrong? I made a simple reference dipole of 2x17cm CU wire.
With this dipole the signals where totally worse. So the Diamond does work?
I got curious to look inside. Maybe moisture penetration degraded the antenna.
This  antenna is rainwater close in its normal vertical mounting position. But take care if your mast can b…

Nice opening10m and 12m to S.A.

SFI  low 70 a 16 K3  still 10m opened up in afternoon to N-Italy EA5 F JN33
F/PD0OHW/M in JN33 decoded 150mW

VP8LP  12m    2-way with GP 7m ag swr 1:3

60m 5,362 open to ZL every? morning