Avo 8 Repair - UK Vintage Radio Repair and Restoration Discussion Forum

kenneth · 23rd Feb 2006, 12:20 pm

Have the following two minor problems with my AVO 8 (no mark).

(i) Scale-glass loose. Is there a recommended glue for fixing it? Have tried
copydex without success.

(ii) The meter pointer will not zero accurately. The resting place for the
pointer can be adjusted by turning the appropriate small bakelite
screwhead below midscale but the minimum reading
achievable is 1 - 2 volts rather than zero. Does anyone know how
to get the idling pointer to rest at zero?

Tks. Ken

Station X · 23rd Feb 2006, 12:31 pm

See this thread re fixing the glass back in meters.

https://www.vintage-radio.net/forum/...ht=meter+glass

Ed_Dinning · 23rd Feb 2006, 1:39 pm

Hi Ken, there is also a back adjusting screw on the rear of the movement when it is removed from the case that will allow some further adjustment.
Hold the meter in 3 different planes (vertical, horizontal etc) and see if the pointer moves by more than a small amount. If it does then the movement is out of balance and the small "springs" on the cross arme need to be re-set. I think there is a link to a site with the Avo manuals available for down load.

HTH Ed

calamero · 24th Feb 2006, 2:11 am

Hi ken i found an ftp other night that contains manuals and service manuals for AVO meters while getting one for my avo electronic test meter i seen one for the avo model 8..ill attach it here if poss ok..

ah its too big ill add link below..theres 2 manuals on the ftp

1..is the user manual.. which contains info on how to use it and lots of fault finding and service tips..

"
Manual for Model 8 Universal Avometer Mk II. Compliments of Henrik Ros.

_ftp://bama.sbc.edu/downloads/avo/8-mk2/

a lot of information is repeated from this into the service manual below

2..Service manual

Servicing Guide for repairing Avometers. Compliments of an unknown contributor.

_ftp://bama.sbc.edu/downloads/avo/avo8service/

Good luck i fixed mines other day so its poss

calamero

kenneth · 27th Feb 2006, 10:33 am

RE my request for advice .

G4ILN - Thanks for pointing me to the thread about fixing
Avometer glass. Have ended up using Araldite
(mainly because it was to hand) and hope I
have no cause to remove it in the near future.

Ed - Looked at the back of the meter assembly but
could'nt see a back adjusting screw. There is
a tiny hole through which there may be access
to the rear springcoil but am hesitant to start
touching it without knowing what I'm doing.

Calamero Thanks for the link to the Avometer servicing guide.
Tried downloading it and all seemed well except
that the downloaded document appeared as blank
pages and blank thumbnail indices. Don't know
whether its my problem or theirs. Will try again.

Thanks to all - Ken

Station X · 27th Feb 2006, 11:18 am

When downloading stuff frm The Boat Anchor Manuals Archive (BAMA) it's best to use the mirror site, which in the case of the AVO Model 8 is here:-

http://bama.edebris.com/manuals/avo/avo8service/

plumbweiss · 21st Nov 2006, 9:53 pm

If the meter won't zero, it may well be that the hairspring(s) are a little tangled. Overload or dropping can cause the spring to not lie flat (ie go cone shaped) or even for one turn to overlap the other, leading to friction. Examine the back and front spring (you'll need to remove the movement completely from the instrument) carefully and check that no spring turn touches the other at any point around the spiral. If it does, use tweezers to tweak the anchorpoint of the spring slightly to give them a more even appearance. This is a very delicate part of the meter, you might find a non-ferrous tool better at this stage. The bearings can be adjusted from both sides, if they pinch the needle points then friction is again produced and this will also prevent the needle zero'ing properly. The coil should be equidistant from the magnet core to prevent binding.

23rd Feb 2006, 12:20 pm	#1
kenneth Retired Dormant Member Join Date: Apr 2005 Location: Cheltenham, Gloucestershire, UK. Posts: 173	Avo 8 Repair Have the following two minor problems with my AVO 8 (no mark). (i) Scale-glass loose. Is there a recommended glue for fixing it? Have tried copydex without success. (ii) The meter pointer will not zero accurately. The resting place for the pointer can be adjusted by turning the appropriate small bakelite screwhead below midscale but the minimum reading achievable is 1 - 2 volts rather than zero. Does anyone know how to get the idling pointer to rest at zero? Tks. Ken

23rd Feb 2006, 12:31 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Avo 8 Repair See this thread re fixing the glass back in meters. https://www.vintage-radio.net/forum/...ht=meter+glass __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

23rd Feb 2006, 1:39 pm	#3
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,196	Re: Avo 8 Repair Hi Ken, there is also a back adjusting screw on the rear of the movement when it is removed from the case that will allow some further adjustment. Hold the meter in 3 different planes (vertical, horizontal etc) and see if the pointer moves by more than a small amount. If it does then the movement is out of balance and the small "springs" on the cross arme need to be re-set. I think there is a link to a site with the Avo manuals available for down load. HTH Ed

24th Feb 2006, 2:11 am	#4
calamero Retired Dormant Member Join Date: Feb 2006 Location: uk Posts: 4	Re: Avo 8 Repair Hi ken i found an ftp other night that contains manuals and service manuals for AVO meters while getting one for my avo electronic test meter i seen one for the avo model 8..ill attach it here if poss ok.. ah its too big ill add link below..theres 2 manuals on the ftp 1..is the user manual.. which contains info on how to use it and lots of fault finding and service tips.. " Manual for Model 8 Universal Avometer Mk II. Compliments of Henrik Ros. _ftp://bama.sbc.edu/downloads/avo/8-mk2/ a lot of information is repeated from this into the service manual below 2..Service manual Servicing Guide for repairing Avometers. Compliments of an unknown contributor. _ftp://bama.sbc.edu/downloads/avo/avo8service/ Good luck i fixed mines other day so its poss calamero

27th Feb 2006, 10:33 am	#5
kenneth Retired Dormant Member Join Date: Apr 2005 Location: Cheltenham, Gloucestershire, UK. Posts: 173	Re: Avo 8 Repair RE my request for advice . G4ILN - Thanks for pointing me to the thread about fixing Avometer glass. Have ended up using Araldite (mainly because it was to hand) and hope I have no cause to remove it in the near future. Ed - Looked at the back of the meter assembly but could'nt see a back adjusting screw. There is a tiny hole through which there may be access to the rear springcoil but am hesitant to start touching it without knowing what I'm doing. Calamero Thanks for the link to the Avometer servicing guide. Tried downloading it and all seemed well except that the downloaded document appeared as blank pages and blank thumbnail indices. Don't know whether its my problem or theirs. Will try again. Thanks to all - Ken

27th Feb 2006, 11:18 am	#6
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Avo 8 Repair When downloading stuff frm The Boat Anchor Manuals Archive (BAMA) it's best to use the mirror site, which in the case of the AVO Model 8 is here:- http://bama.edebris.com/manuals/avo/avo8service/ __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

21st Nov 2006, 9:53 pm	#7
plumbweiss Retired Dormant Member Join Date: Nov 2006 Location: Manchester, UK. Posts: 157	Re: Avo 8 Repair If the meter won't zero, it may well be that the hairspring(s) are a little tangled. Overload or dropping can cause the spring to not lie flat (ie go cone shaped) or even for one turn to overlap the other, leading to friction. Examine the back and front spring (you'll need to remove the movement completely from the instrument) carefully and check that no spring turn touches the other at any point around the spiral. If it does, use tweezers to tweak the anchorpoint of the spring slightly to give them a more even appearance. This is a very delicate part of the meter, you might find a non-ferrous tool better at this stage. The bearings can be adjusted from both sides, if they pinch the needle points then friction is again produced and this will also prevent the needle zero'ing properly. The coil should be equidistant from the magnet core to prevent binding.