This morning, Graham and I rode the mini-bus, a Toyota Regal, that Salema was driving to work.  There were eight of us.

There were a total of 14 men at morning devotions, which is the highest number that I can remember, and we were missing Steve and Klaus, who had meetings in town all day.

Virginia made oatmeal cookies with chocolate chips last night and sent about three dozen to work with me.  I set them out at lunch time and they disappeared quickly.

I worked on emails this morning while the transmitters were on the air.  Then Graham and I did some more diagnostics on TX2 and determined that the erroneous switching off of the filaments is being done by the computer, rather than the fault latch card or the ‘cooling off ‘ command.  This narrows the search down, but will likely be more difficult to track down further, since it looks like the solution may be hidden in the transmitter’s computer program.

I have been fairly certain that the automation system has been switching the transmitters to ‘quarter power filament’ nearly every time it switches ‘driver off’.  I have been adamantly told this is not being done by the automation program.  Today, with Hans’ help, we figured out that the problem is not in the program, but in the circuitry used for interfacing to the transmitter.  Hopefully by removing one diode and adding three diodes, this problem can be corrected.  Since this was discovered near the end of the day, we decided to wait until Monday to make any changes.  It am not certain that this will eliminate all the problems, but there should be considerable improvement.

Rummikub tiles can be used for more than just playing games.

In Swaziland we do not get the day off for the U.S. Independence Day, so it was work as usual.

Today Graham and I continued our research into the filament issues of the transmitters that are causing intermittent problems.  This has involved using a digital oscilloscope to monitor currents and voltages of the filaments with the hope of ‘catching’ and recording these reading when a fault occurs.  We have had some success and need to analyze the results.  Hopefully, it will be possible to eliminate the problems.

I do want to stress that air time is not lost due to these problems, as they only occur when the transmitter is coming up.  Curing the problems, though, will make the operators’ work less stressful and increase the life of the transmitter tubes, which cost over $17,000 each new.

Virginia tutored the little girl again to day.

Ruth and Virginia looking at a handmade wallet.

In staff meeting we heard testimonies from all three interns — Jonathan from Virginia, Samuel from Canada and Sifiso from Swaziland.

After staff meeting, we picked up Ruth from her home and went shopping at the Manzini Market.  Most of our time was spent at the craft market, but a few vegetable were purchased in the old market building.

For lunch we went to Molly’s House of Grills in the Riverstone Mall.  [I made an error in a previous post by referring to it as the Riverside Mall, although it is beside a small river]  The ladies had fish and chips with salad, which was much less greasy

Looking down from the craft market on the tent booths and ‘garage’ shops — mostly clothes are sold, here with some herbs used by traditional healers.  The taller building in the back left is the vegetable market.

than the Fish O Chips place next door where we ate before.  I had a 1/4 chicken with chips and salad.  The total bill with drinks was about $10.

When Virginia and I got home in the afternoon we both took naps.  With not much break over the weekend, we were both very tired.  Of course, I get more tired after three hours of shopping than a whole day of work!

I spent a couple of hours writing up a report on what we have found out so far about transmitter tube filaments issues.

We had an early supper then stopped by Pick N Pay to get some grocery items on our way to prayer meeting.

Inside the vegetable market, which has remained unchanged in 40 years. Usually it is MUCH busier than this.

Ruth purchased some carrots here. Note that the vendor is wearing a T-shirt with an American flag, probably for a used clothing shipment from the U.S.

Pastor Healy spoke on the little book that Peter ate in Revelation 10: 2, 8-10.  His conclusion was that the little book is the Bible, since it is an open book and made public, unlike the closed and sealed book in Revelation 5

Before turning in for the night, we had a good ‘chat’ with Joyce using  Skype texting.

A sheet metal shop in one of the ‘garage’ shop spill out into the walkways.

This is in Manzini, Swaziland — escalators inside the Riverstone Mall!  Notice that the left one goes up — just like one has to drive on the left side of the road in all of southern Africa.

Ruth and Virginia eating lunch at Molly’s house of Grills. Yes, Coca Cola has been in Swaziland for over 40 years.  It is reported that “Swaziland supplies the Coca-Cola concentrate (the sugary syrup the drink is made from) to most of Africa, big parts of Asia and all of Australia and New Zealand from its industrial plant in Matsapha.”  This accounts for at least 22% of the GDP of Swaziland.

After all the work done on TX3 yesterday, it performed well last night.  After the broadcasts this morning, the driver tube removed yesterday was reinstalled.  It is believed that the only problem for all of the chaos yesterday was due to the bias supply wire with an intermittent connection.  A test transmission revealed no problem with the driver tube.

Graham and I set up a digital oscilloscope to capture the filament voltage of TX3 during various ‘turn on’ scenarios.  This information revealed the reason for a problem experienced when switching the filament from what the transmitter thinks is ‘quarter power’ to full power.  The computer does not ‘know’ the quarter power feature in TX3 has been disabled.  As a result, occasionally the filament circuit breaker trips and now we think we know why.

While we were doing this, Salema and Sifiso (a Swazi intern) discovered a water leak on TX1 and it appeared to be from the same place as the leak Graham and I ‘repaired’ last week.  I gave them instructions on how to remove the four back doors and top trim to get access to the area of the leak.  It was discovered that the leak was coming from the top seal of one of the radiator tubes located just above the fitting we ‘repaired’.  This time the leak was discovered immediately after shutdown and the water drops were still running down, instead of just a puddle of water being found.  Swaziland does not have the tool to remove this tube to replace the seal.  Since it is a slow leak, and not under pressure, silicon sealant was used in an attempt to stop the leak and a pan was placed under the radiator to collect any drips before they can cause damage to the electrical components below.  TX1 has been in service for 21 years.

We had the interns, Jonathan and Samuel over for supper this evening.  After supper, Klaus came by to show Samuel, a computer major, the ‘hub’ located at Singing Pines where the internet signals are received via a link from the transmitter site and distributed to the five houses via fiber optic cables.  Our phones also use this internet connection.  Fiber optics are being used because lightning has destroyed previous systems.  Lightning storms are very frequent and severe here in Swaziland and Singing Pines is on the top of a hill.

When listening at ‘home’ to one of the transmitters this morning, I heard it go off the air at 5:41am.  When we got to the site, Salema, the technician on call, was already there trying to get it on the air.  Earlier, some of the air piping had come apart and that was repaired, but now the Driver Bias voltage was not ‘ramping up’.

Initially, it looked like the Bias Supply circuit breaker was faulty, so that was rectified.  In the process of troubleshooting that problem, a 110 volt wire came in contact with the circuit breaker’s auxiliary switch, which created another problem that had to be traced and corrected before proceeding.  A resettable fuse for one of the 24 volt circuits had been destroyed and had to be replaced.

Back to the bias problem, we measured zero driver grid bias, but the supply had voltage going to it.  We decided removing the driver tube was the fastest way to check for a grid short.  When this was done, the bias voltage returned to normal, so a new tube was installed.  Eventually, the apparent circuit breaker problem returned and it was found that one of the wires bringing the 110 volts supply to the breaker had been inserted into a terminal block in such a way that the screw that was supposed to clamp the wire was clamping the wire insulation instead.  The connection would come and go depending on the position of the wire.  Now it should work — WRONG!

The transmitter would still not come on.  It appeared that there might not be enough RF drive, but the RF drive controller appeared to be working.  RF measurements from this transmitter were compared to one of the other transmitters.  The measurements were slightly lower.  After much searching, we found that the RF Drive controller voltage was limiting at about 3 volts.  This board was swapped out and everything returned to normal.  We found that the 15 volt regulator on the board had failed and another lower voltage supply was back feeding.  This gave the appearance of it working.  This regulator was replaced and the board was put back into service.

After all that has been done, we are not sure now whether the original driver tube was bad.  It may have been an intermittent breaker supply wire all along.  That driver tube will now be tested with a high voltage tester.  If it checks out OK, it may end up going back into the transmitter for testing.  If it passes that test, then it might be used for broadcasting again.

I spent the time after lunch locating the quarter power filament drawing and schematics.  There are a couple dozen files that I need to study before proceeding with troubleshooting the filament anomalies, which had been our original objective for today.  Maybe tomorrow!