I had this morning free and really needed to get into the workshop to complete a few repairs, there was also a 37″ Samsung that had been dropped off at our house to look at, and a customer just around the corner with a 26″ Sony that was freezing on channel change, then rebooting itself. I had a nasty feeling this was another software problem associated with the BBC red button, the clue…it only happens on BBC channels! I said I would take it into the workshop to check it over and perform a software update, if this didn’t work there would be very little I could do.
First onto the bench was the Samsung, we had been told it was dead, in actual fact it had a solarised picture, this is an effect similar to an over exposed photo, so the fault was diagnosed and the part ordered. Next was the Sony, I entered the service menu, did a factory reset and updated the software. That was put on test, I wasn’t expecting to see it go wrong, I’ll only know if it’s sorted after it’s been back with the customer for a while.
Next was a JVC turntable, not a good quality one I’m afraid and it had already been fiddled with by someone else, the fault…the tone arm wouldn’t automatically return at the end of the record, the cause…a very slack drive belt and a dirty micro switch, unfortunately the fiddler had destroyed a spring on the return mechanism and in the end the best I could do was get it to return to its resting position but it needed a little push on the platter to get it to actually complete the return cycle.
I’d been looking forward to the next one, a very nice 1970’s Pioneer receiver that lit up nicely but had lost output on both channels. As each channel had it’s own STK type output IC I decided the problem was very unlikely to be in the output section, nor the preamp or there would be some kind of noise from the outputs. There was definitely a supply voltage missing, luckily the owner of the amp also had the original circuit diagram, what a godsend that was. All voltages were correct at the outputs and the supply to the preamps was also present, checking further I found the 40 volt regulator had no output, this came straight off the mains transformer, through a fuse, which was ok, through a single rectifier which was also ok, I could measure 50 volts on it’s Cathode, between here and the regulator there was just a network of resistors, the first of which, a 33 ohm 1 watt, was open circuit. I checked for shorts in the regulator and found none so replaced the resistor and all worked well. It’s so nice to be able to keep this kind of lovely old Hi Fi going. I noticed, looking at the components inside the amp, that all parts looked in very good condition, that doesn’t always mean much with electronics but in comparison I’ve seen one year old ( or less ) TV’s with bulging capacitors and heat damaged panels!
Back to more modern equipment for the afternoons jobs, the first call was yet another Panasonic DVD Recorder recording the channel list, I explained that this was caused by the BBC software and that there was nothing I could do, by now I was a little fed up doing factory resets and retunes with no hope of it fixing anything, the customer was happy enough to just record non BBC channels on the DVD’s hard drive and do the BBC channels on the Humax box they also owned.
A couple of Humax HDR’s to install and a repair to deliver back to finish the day, not very stressful hey! Well the first install was a bit frustrating, a brand new Humax Freeview + hard drive recorder, a very nice piece of kit except, on installation it kept shutting itself down and rebooting and occasionally changing channels on it’s own. I decided it must be something incompatible with the almost new Panasonic TV. I went through the menus and disabled the viera link which was of no use to the customers, at which point the box started behaving itself. This wasn’t the end though, I was called back half an hour later because it was doing the same again, I tried a different HDMI lead, a different input on the TV and even another new box but nothing worked, the plan now is to return with a Panasonic HDR which I’m sure will be ok, there’s obviously something in the house that the Humax doesn’t like. That box behaved perfectly all evening in my own home…as I knew it would!