From barrie at look.ca Thu Mar 15 14:31:25 2012 From: barrie at look.ca (Barrie Robinson) Date: Thu, 15 Mar 2012 16:31:25 -0400 Subject: [Mgb-v8] Slash Panel Message-ID: I have a splash panel (Moss part number 458-390 or 458-395?) left over. It is new but beautifully black powder coated and I would like $10 plus postage for it. Anyone interested? Regards, Barrie Robinson barrie at look.ca 705-721-9060 MGB GT V8 in great nick Aston Martin 1955 DB 2/4 MkII under restoration www.britishv8.org/MG/BarrieRobinson.htm www.britcot.com www.AMFClub.com From paul.hunt1 at blueyonder.co.uk Tue Mar 27 01:51:30 2012 From: paul.hunt1 at blueyonder.co.uk (Paul Hunt) Date: Tue, 27 Mar 2012 08:51:30 +0100 Subject: [Mgb-v8] Dynamo output reverses Message-ID: During a track-day a pal noticed his dynamo had stopped charging. We removed the leads to do a dynamo output test and I connected the meter leads and noticed a small negative output. "Stupid boy", I thought, it's positive earth (I'd connected the meter as I would on my alternator-equipped cars) but the owner said it was negative earth. Checked my meter on the brown lead at the fusebox and sure enough that showed positive 12v, but on the dynamo output terminal (no wires connected to either terminal) I still had this small negative voltage. It should be a small positive voltage, as that is fed back to the field winding by the control box, which generates a bigger output, which fed back to the field generates even more output and so on until the control box connects the output to the battery to start charging. Pal thought it was brushes, but a resistance check on both field and output showed a very low resistance as I would expect. Even tried flashing the field from the brown at the fusebox but it made now difference. Subsequently pal changed the brushes but that made no difference either. Any ideas? PaulH. From jaguarsandrail at hotmail.com Tue Mar 27 17:10:58 2012 From: jaguarsandrail at hotmail.com (James Bown) Date: Tue, 27 Mar 2012 17:10:58 -0600 Subject: [Mgb-v8] Dynamo output reverses In-Reply-To: References: Message-ID: If you are really certain that the field winding is OK (not open) then it would likely be the regulator (control box). But it is difficult to troubleshoot such things from a distance. Please let us know what you find the solution to be. Regards, Jim B. Salt Lake City > From: paul.hunt1 at blueyonder.co.uk > To: mgb-v8 at autox.team.net; mgs at autox.team.net; MG-MGB at yahoogroups.com > Date: Tue, 27 Mar 2012 08:51:30 +0100 > Subject: [Mgb-v8] Dynamo output reverses > > During a track-day a pal noticed his dynamo had stopped charging. We removed > the leads to do a dynamo output test and I connected the meter leads and > noticed a small negative output. "Stupid boy", I thought, it's positive earth > (I'd connected the meter as I would on my alternator-equipped cars) but the > owner said it was negative earth. Checked my meter on the brown lead at the > fusebox and sure enough that showed positive 12v, but on the dynamo output > terminal (no wires connected to either terminal) I still had this small > negative voltage. It should be a small positive voltage, as that is fed back > to the field winding by the control box, which generates a bigger output, > which fed back to the field generates even more output and so on until the > control box connects the output to the battery to start charging. Pal thought > it was brushes, but a resistance check on both field and output showed a very > low resistance as I would expect. Even tried flashing the field from the > brown at the fusebox but it made now difference. Subsequently pal changed the > brushes but that made no difference either. Any ideas? From paul.hunt1 at blueyonder.co.uk Wed Mar 28 01:41:28 2012 From: paul.hunt1 at blueyonder.co.uk (Paul Hunt) Date: Wed, 28 Mar 2012 08:41:28 +0100 Subject: [Mgb-v8] Dynamo output reverses References: Message-ID: <01D1346F9BD041C9A8523B94CC04F848@paul> The control box wasn't connected at the time I was getting the negative voltage from the (should have been positive) output terminal. Apparently when they changed the brushes it became obvious that the bearings are shot, so if the armature is flapping about that could cause all sorts of problems. It remains with said pal to see if he will replace the dynamo as has been recommended. PaulH. ----- Original Message ----- If you are really certain that the field winding is OK (not open) then it would likely be the regulator (control box).