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Re: Which software version next?

Hi Adrian! Thank you for your quick answer. I have been so busy that I have not had time for answering so far. You are fully right and I old fashion! :D I have already agreed with one hammate that he helps me uploading the new software which you shared for me. When the case is closed I will give fee...
by OH2NOS
16 Mar 2014 18:28
 
Forum: Juma Discussion
Topic: Which software version next?
Replies: 5
Views: 2840

Which software version next?

Hi! I assembled own Juma two years ago and have used it very satisfied. So far I have used cw only, but now couple of time tested ssb also. With ssb I have met problems time to time because SWR seems to be too high (even it is not) and output goes down. Then I remembered that somebody spoke about th...
by OH2NOS
11 Mar 2014 08:22
 
Forum: Juma Discussion
Topic: Which software version next?
Replies: 5
Views: 2840

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi All! My problems with Juma are history now or have been history long time already. I have only forgotten inform what has happened. So Juma has been in use couple of months and personally I am more than delighted customer! :D When I did my last fixing I did an error: I bought new TR3 and 4 but the...
by OH2NOS
08 Jun 2012 09:09
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi Robert!

Thank you for your hint! But I suppose that contamination is more optical illusion than truth. The most probably error is contamination between my ears. :D

My Juma is now “in better hands” and let see what he will find for the root cause of my problems.


73, Saku OH2NOS
by OH2NOS
29 Feb 2012 12:13
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

TRX2 Main Board, RX section

I have been out of hobby last month, but now I have time again. I have still the problem that my Juma TRX2A doesn’t work. Before when I listened, I heard nothing even I added gain. 1) Then I decided to change TR3 because I assumed it been defected, because nothing happened when I pressed tangent dow...
by OH2NOS
26 Feb 2012 20:18
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi Matti! Yesterday I made couple of measurements based on Main board voltage table (Appendix E). Now I have checked receive state only (Mode LSB, f = 3.7 MHz, Filter WID, AGC slow, Speechproc OFF, NB OFF, MIC input, dummy load). Here I present findings which are not according to the table. OPAMP A1...
by OH2NOS
20 Jan 2012 07:30
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi Matti! I have been out of hobby last two weeks, but now I inform that 10V line is up and running. When A10 and A11 was turned in correct position output voltage of REG 2 was 10,2V (or 10,3V), but anyway the reason of problem was wrong position of A10 and A11. I make more stupid question for becom...
by OH2NOS
18 Jan 2012 12:35
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi Matti! I checked the Filter 1, its resistance between pins 2 to 3/4 is 7,2 kohm. Previous measurements I made with pure Main Board without Filter 1. The whole resistance, when Filter 1 is connected, between C64 (+) and ground is 3,9 kohm. Then I checked A1 to A11 with magnifying glass against lay...
by OH2NOS
06 Jan 2012 21:14
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi Matti! I have good and bad news for you - bad first! I have not been able to fix the problem with 10V power supply. Good news is that I have done lot of measurement for tackling the problem but without success. Measurements which I have used are Fluke 179 Multimeter and Fluke 105B Scopemeter. 1. ...
by OH2NOS
06 Jan 2012 13:09
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140

Re: Juma TRX2A - Voltage supply problem in Main Board

Hi Juha! Life goes on but some problems stay. Some progress has happened. First, I downloaded datasheet of LP2950 (2951). Now I got better understanding about pins and their meaning. Reg 1: Pin 2 was badly soldered and it is now connected to pin 1 and the regulator works correct! Output voltage is 5...
by OH2NOS
03 Jan 2012 20:50
 
Forum: Juma Discussion
Topic: Juma TRX2A - Voltage supply problem in Main Board
Replies: 17
Views: 12140
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