Search found 33 matches

by Ridgeback
Wed 03 Feb , 2016 0:51 am
Forum: Machines
Topic: What is this boxford thing for ?
Replies: 5
Views: 8537

Re: What is this boxford thing for ?

Hi Guys, This bit of kit is a “Comparator”, it compares your turned or milled part to a given size. You set the Comparator by placing a pack of slips of known size between the clock plunger (pointed end) and the base. The Comparator is then lowered onto the slips until the indicator is in the ZERO o...
by Ridgeback
Thu 19 Nov , 2015 23:09 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, My plan to make checking easier has worked. I now have a set of results which I think are more useable than before. I used TB1/2 as my checking (Datum point) for all the locations on the circuit board I wanted to check and below are the results I found. I used a digital multi-meter. 7805 inp...
by Ridgeback
Tue 17 Nov , 2015 23:38 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, The 0.5A fuses arrived, are in place and this is what I found. Between Terminals 2&3 on TB1. +ve lead on T2 & -ve lead on T3 = +12 volts. Between Terminals 2&1 on TB1. +ve lead on T1 & -ve lead on T2 = +12 volts. Between Terminals 2 on TB1. & Output line of 7805 regulator. -ve lead on T2 & +...
by Ridgeback
Sun 15 Nov , 2015 22:26 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, Back from my trip and ready to go again, or so I thought. I had doubts about my checking of the Op-amp results as I did not fully understand the configuration of the 8 pins. A bit of research showed this to be true so I went back to double check my results. I had nothing from Pin 6 of the op...
by Ridgeback
Fri 06 Nov , 2015 15:59 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, Thanks for that. As I said, I will not be able to go ahead and do any checking as I need to pack kit ready to go. Your first point, it was a typo, I meant TB1/2. Your explanations from point 2 onward seem pretty obvious now as I read them. I didn't think to continue checking further down the...
by Ridgeback
Fri 06 Nov , 2015 0:29 am
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, Not too sure about what conclusions I have come to, but here are the results to the test I carried out this evening. TB1/4 and TB1/5 with motor running (approximately 10 RPM) and my meter set on 2.5 V dc, NO movement at all. TB/2 as reference: ( Black lead of meter here). At collector of ZTX...
by Ridgeback
Wed 04 Nov , 2015 19:52 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, WOW, this is getting deep. I have a prior engagement tonight so will only be able to attempt the above checks tomorrow. I am not sure what I checked a couple of days ago, but due to the extremely slow running of the motor I did get a reading which caused pulsing of the meter needle. Will hav...
by Ridgeback
Wed 04 Nov , 2015 0:17 am
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, Running a bit late today as I had two small jobs to do on my trusty old Boxford lathe. Well spotted with the odd page number missing issue. I hadn’t noticed that. I put the meter across the L&N lines on the Brown Pestell Controller terminals and there is 250V ac there. I also tried across th...
by Ridgeback
Mon 02 Nov , 2015 22:27 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, Thanks so far. It is a bit late to go out to my garage to do the next suggested checks so I have spent some time indoors looking up what I though I had remembered seeing some time ago. I eventually found this to do with the Brown Pestell Controller and have attached it for you to look at. I ...
by Ridgeback
Mon 02 Nov , 2015 20:08 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, These are the results I found using a standard analogue multi-meter. Where –ve voltages were present I had to reverse the connections to ascertain a reading. Between Terminals 2&3 on TB1. +ve lead on T2 & -ve lead on T3 = +12 volts. Between Terminals 2&1 on TB1. +ve lead on T1 & -ve lead on ...
by Ridgeback
Sun 01 Nov , 2015 23:00 pm
Forum: Orac
Topic: Orac replace jaw
Replies: 3
Views: 2472

Re: Orac replace jaw

Hi Gabriele, Not sure if this is going to be of help to you, but there are two complete Orac Yamakawa chucks, with mounting plates, for sale on Ebay at the moment. They are in the States which could be a problem though. The numbers to dial in are 261876064686 and 390750269950. Keep turning. Cheers C...
by Ridgeback
Sun 01 Nov , 2015 22:16 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Re: Orac spindle drive problem

Hi Max, Thanks for your response. Being new to this forum, I am feeling my way in so don't be alarmed if I pig up a little here and there. I found this link on this forum under Orac and the two drawings found on Pages 18 and 19 are the ones which relate to the 10v zener diode line. The actual drawin...
by Ridgeback
Sun 01 Nov , 2015 15:16 pm
Forum: Orac
Topic: Orac spindle drive problem
Replies: 21
Views: 6974

Orac spindle drive problem

Hi All, Having read many of the blogs on your forum pages relating to Orac spindle drive issues, I am sure you are going to be thinking, oh no not another one!! I am afraid it is true, yes another one. I have recently acquired an Orac which was running fine when I viewed it and collected it but is n...