Satellite Workshop 23
Recently people have pointed out that my articles often contain more
Pace faults than any other make. "Surely, Pace receivers must be very
unreliable" commented one reader. Well, this is not really true.
There are several factors involved. Firstly, more Pace receivers were
sold in this area than any other make. Secondly, customers like them
so much that they prefer to have them repaired rather than scrap
them. Thirdly, parts are available even for eight year old Pace
receivers and, fourthly, service information is willingly given by
Pace Technical department. The combination of these factors, plus
Pace's openness about any problems, means that dealer loyalty and
customer loyalty remains high. With the truly unreliable receivers,
you would be reading about the same faults month after month. Nobody
wants to read about replacing start-up resistors time after time -
which is why I write about Pace receivers instead!
Yesterday I had a telephone call from London. The customer described
the problem as "horizontal streaks on decoded channels." This was on
an IF distribution system and, apparently, several receivers
exhibited the problem in the same location. I suspected a batch of
faulty decoder I.C.s but Nokia Technical proved me wrong. They
suggested that the customer was mounting the receiver too close to
his television and that interference radiating from the TV was
creating the effect. They were correct. The receiver was actually on
top of the TV. Moving it to a side table cured the problem. Now, I've
pointed out that a receiver should not be placed on top of other
equipment because it can cause overheating and can also radiate into
the TV but this is the first time I've come across the opposite
effect.
The local carpenter is Welsh. To be more accurate he is from
Anglesey. I won't try to pronounce the name of his village but it
ends in "gogogoch." Everyone calls him "the artful bodger." I don't
know how he ended up in Yorkshire and he certainly hasn't learned the
language.
"This satellite receiver by hyur dusan't wurk no more look you," he
sang, spilling wood shavings across my floor. "When I press this
button he flashes minus three then goes back into standby."
He left the unit with me and I looked inside it later that day. A
generous filling of sawdust had kept it nice and warm and I guessed
that the electrolytics had dried out. Replacing C5 (100 F) and C10
(10 F) in the power supply got it running but the decoder messages
were pale grey and the 5 volt supply measured 4.5v. I changed C13
(470 F) and C14 (1000 F) in the power supply and the decoder messages
went nice and dark. The power supply output was now 5.05v which is
correct but I noticed that the decoder messages flickered as I put
the meter probe on the connector plug. A squirt of switch cleaner and
a wiggle cured this bad connection.
My accountant probably won't believe the receipt which reads "Paid
with thanks: one rolling pin, one dibber and a garden chair in
payment for SRD500 repair." Well, we still like to barter around
here. I hope the baker has a fault soon; I'm feeling hungry!
While I was on the way to drop off repairs for a local shop, I
received a call on my mobile telephone. The lady's Cambridge ARD200
was dead and her husband said it needed a fuse. Her address was only
a short detour off the main road so I called in to collect the
receiver. The woman showed me into her living room then trotted off
to watch TV in the kitchen. I spent an exhausting ten minutes
extracting the receiver from the floor-to-ceiling cabinet which had
to be lifted to release the mains cable upon which it was
standing.
Having finally freed the captive receiver, I poked my head around the
kitchen door to tell the lady that I'd be back with it in the
morning.
"Oh, you can't take it away!" she exclaimed. "My husband's an
electrician and he says it just wants a fuse."
I explained patiently that I would need to take it to the workshop to
find the cause of the melted fuse, if in fact that's what the problem
was. I don't carry fuses in the van and it needed a Torx number 10
screwdriver to release the cover.
"Oh, you can't take it away!" she exclaimed. "My husband's an
electrician and he says it just wants a fuse," she repeated, as if I
hadn't said a word.
I handed the unit over to her, smiled and walked out of the house,
silently grinding my teeth.
"Do you know where I can buy a fuse?" she shouted.
"Ask your husband -- he's an electrician!"
Made by The Orient Power Video Manufacturing Co., which made the
Oritron/Aegir/Dixi/Lenco D2Mac decoder, this receiver is sold under
the "BT" badge.
I had two for repair, today. The first exhibited
"decoder messages disappear after warm up". Replace C45 (1uF next to
U6 PTV111) often effects a cure but, on this occasion, C38, 33nF
polyester caused the problem.
It measured correct but must have been leaky.
The same receiver had apparently had a previous fault described
as
"Pattening" (sic) which was cured by replacing D15, L6 and C29 at
the
back right corner of the decoder board (located with hair-drier
and
freezer aerosol by the dealer who fixed it). However, another
fault
appeared after warm-up: At switch-on the display would show "LNB5"
then
"OFF". ("LNB5" is actually "LNBS" meaning "LNB Short-circuit")
In fact, there was NO short-circuit and the LNB voltage under load
was 14v dc. The dealer posted it to me. I traced this fault to Q407
(2SC1815) and Q406 (medium power PNP) next to heatsink. Luckily I
have a poor photocopy of a photocopy of what they laughingly call
"the circuit diagrams" -- barely readable but at least I was able to
figure out the LNB supply circuitry (although the fault was in the 12
volt regulated supply!)
The other SVS250 had symptoms which I've not seen previously:
On changing channel I could see only a blank screen for a couple
of
seconds until the picture appeared. On channel 18 (possibly others,
too) the
screen (Cartoon Channel) remained blank. After replacing every
electrolytic on the main board, I found it was C173 (47nF green
coloured
polyester cap) in the middle of a cluster of electrolytics just right
of
the tuner.
As a precaution, I replaced C460 (100 F) next to the heatsink. This
causes a herringbone pattern which customers often describe as "loses
colours when warm."
These BT receivers are now "dropping like flies" and should be
good
little earners for a few months.