In your detailed photo, it's the resistor right next to the + lead that really shows sign of damage - whereas the other one indicated the resistance I mentioned, but, of course, if you say both have that (same) value, then it was my measurement that was inaccurate. This 2nd resistor is surely damaged too as I said from the beginning although it doesn't entirely look so.
Let's see if I can find a pair and replace them, then it's the MOSFETs.
I did manage to find both MOSFETs as well as the 0 Ohm SMD resistors, so I'll start by replacing the damaged ones and then what happens.
Luckily, those 2 resistors aren't on a too much "crowded" area, but I wouldn't want to perform the desolder / solder operations myself as I lack the equipment for this sort of SMD stuff, so I'll look for somebody else to do it; if not, I have no other means but to try the "tradition" approach.
This is to let you know, that I finally got a message from RFsource days ago whereby the owner (?) explained none (!) of my earlier messages were received, only the latest one complaining for a lack of response. The "culprit", he explains, may have been an anti-virus prgr that blocked some mail... but no message was returned.
Since he agreed to check both items - the PLL exciter & the "pallet" amp. -, I mailed it today, so let's wait and see what happens.
Having said that, I have no objection *whatsoever* in withdrawing the previous comments I issued here, and if the goods are actually properly checked and returned in operation order, then, again, no objection in sjuggesting this company to others in the milieu.
Further to my 31st May last post, and in view of the developments with this RFsource stuff, I feel the obligation to explain RFsource, to whom I had sent my MF exciter+amp., has worked on the items and returned them fully interconnected. I got the tx back a few days ago.
Those who provided me some help discussed about the voltage, so now I am awaiting RFsource's comments on using either 12 or 24 so as not harm those PA FETs, meaning I won't even dare to use 12 V= to see how it goes.
So I must only praise RFsource for their assistance, and if the initial failure of contact was indeed due to what they explained after a lot of time waiting for such assistance, then my harsh words are to be ignored.
The antenna has been waiting for this RFsource tx, and has in the meantime been used with that "other", mystery tx I talked about here. Unfortunately, as I said this one doesn't send on DSB/AM, but carrier+one side band meaning audio quality does leave a lot to be desired...
It's a long time since I last said anything about RFsource and this exciter-amp. of theirs, that I have.
Well, I have decided to add another post, but not specifically to talk about them.
Let me divide this post into 2 parts, viz.:
A) I have been using the tx w/ some success, which merely consists of relaying some radio stn I want and be able to pick my signal on the car radio. Vy. simple, so not a "music stn." at all.
In the middle of this, I have been using this inv. L, but there were changes:
Antenna I reduced the 45 m horiz. portion of the inv. L to just 7.5 m, and kept using the same slanted radiator; of course, there were changes in terms of SWR.
Due to that, I lhave added 3 sloping 7.5 m wires in the hope to achieve higher capacity, and it must have for I experienced changes when using this or that tap on the new inductor.
ATU I finally ordered a 2nd 1,000 pF 1200 V variable capac., installed it, and am stil with the L-C-L variant in T configuration although I briefly tried the Pi configuration for a few days' time. For some reason, the Pi type didn't provide the results I was expecing.
Inductor Instead of the variometer, I made a coil, and the whole thing began to work more smoothly. Detais: abt. 80 turns of 1.8 mm diam., unifilar wire over an 80 cm long, 4 cm diam. form (PVC pipe), taps every 5 turns.
B) Audio & Power Supply.
Audio source. Normally, it's the computer "tuned" to a particular stn I want to relay. When the audio cable is inserted, the RFsource exciter indicated a sligh reflected power increase, then I adjust the ATU according.
Higher audio peaks cause variable SWR/reflected RF. I am still to build an audio limiter as some advised me to do.
However, if I use the JRC NRD-545DSP rx as audio source, something is happening that wasn't when I had the antenna in its primitive shape: the refflected RF warning kicks in and the tx switches to safety mode.
Even connecting the audio cable to the rx causes higher SWR, let alone increasing AF gain.
I don't know how to cure this.
Power Supply. I have ordered a variable V & I model, but it was returned, so I feel it's fair if I say don't used them as they can be affected by RF and "go crazy".
It replacement arrived yesterday - Mean Well for 27 V nearly 6 A. Another disaster! It delivers 30 V, if adjusted, and it's set for 28 V, but when I use it, the max. tx power decreases almost by half and it causes high SWR.
So, the 24 V 6.xx A PS from the broken TV set is what I am still using until I get a solution for the Mean Well model *or* then have a custom made PS built for me. _________________
So a few words of advice: stay clear of RFsource, which I hate to say, and avoid those PS types, get a linear one, even if this means having it built for you, if there isn't anything on the market with the needed tension/current.
More could be said about the antenna & inductor, but this is already a too long speech.