The 75 and ZT Owners Club Forums - View Single Post - Mending stuff

HarryM1BYT · 16th January 2019, 10:49

So many blind alleys, so many people suggesting different fixes and so many potentially differing causes

I made some progress yesterday on this - I managed to get a reliable 4.5Mhz output from Q34, after a bit of tweaking of the value of R18.

I now have reception and audio on part of the VHF band, but it flashes the display to indicate 'no PLL lock' below around 143Mhz all the way down to 160Khz.

I vaguely remember when the flashing display problem first happened, going through the entire PLL section, trying to realign it to fix it - maybe not realising it was the 18 / 4.5Mhz output which was failing, rather than poor PLL alignment.

I now need to go through it all again (long job) and realign it again from scratch - wish me luck

16th January 2019, 10:49	#2
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	So many blind alleys, so many people suggesting different fixes and so many potentially differing causes I made some progress yesterday on this - I managed to get a reliable 4.5Mhz output from Q34, after a bit of tweaking of the value of R18. I now have reception and audio on part of the VHF band, but it flashes the display to indicate 'no PLL lock' below around 143Mhz all the way down to 160Khz. I vaguely remember when the flashing display problem first happened, going through the entire PLL section, trying to realign it to fix it - maybe not realising it was the 18 / 4.5Mhz output which was failing, rather than poor PLL alignment. I now need to go through it all again (long job) and realign it again from scratch - wish me luck __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.