Meazzi Factotum Special repair tips

[Marko H]

Hey

I found a nice project condition Factotum Special Meazzi (tube).
I replaced the power transformer, but something is still wrong. Rectifier anode current rise too much (I put 250mA fuse before rectifier anode and it blows). The rectifier tube heater blows at the end. Where could be the problem? I havent found correct wiring diagram and pictures of a device into the electrical side could help.

Regards
Marko H.
Finland

[keithmantle]

Hi Marko , Try Amanda at www.meazzi.org

[Marko H]

Hey

I have visited Meazzi org websites. There is link to Magnetic echoes but it is not very popular. Messages are not displayed, also guestbook.
Thanks for tipping.

Regards
Marko H.
Finland

[ErikMAMS]

Hi Marko

On Amanda's Meazzi site you will find a selection of schematics incl. a valve Factotum.
Does that - or any of the other schems correspond with your circuit?

Are you sure the new PT is suitable for your circuit?

Erik

[ecca]

What is the AC HT voltage without the rectifier in circuit ?

[Marko H]

Hi

Transformer is original (I found spare part machine). Yes, there is valve model diagram but diagram is nearly right
I measured 600V before EZ81 lines, I think HT is 300V. I suspect the new rectifier tubes are not stable. I had problems with new rectifier tube Vox AC30 -65. HT voltage was 200V with new tube and Nos tube worked properly (HT 305V). SAG resistor could be good choice before new start with Meazzi.

Regards
Marko Haukka
Finland

[Marko H]

Hi

Owns no one in this forum Meazzi Factotum Special?
I have wake the machine on this week. Original fault is unclear but Meazzi is now ready to test. What General Control Meter should read when the machine is switched on (Final A/B position, hf pilot, out put A/B,AC line)?

Cheers
Marko H
Finland

[Amanda]

The circuit diagram on my site is the only one available for the factotum, the metering circuit is not shown
on any version of this circuit I've seen, and all the ones on the web are varying quality copies of this circuit.

Meazzi circuits are very rare..

The trouble with the factotum is that no one seems to use them in their original configuration, most
just using the echo unit and disposing of the power amp and power supply.

I have two Factotums here for repair, both water damaged..

Regarding meter readings, there are 4 coloured zones on the meter:

Final Tubes, Green : Indicates the Voltage on the Anodes of the output valves. (Final A Final B)
AC Line, Red : Indicates The correct AC Line voltage (heater voltage). (AC Line)
HF, Yellow: Give an indication of the AC Bias level (50KHz) for erase and recording. (HF Pilot)
Output Max, Green : Gives an indication of the output level of the amps.. (Output A Output B)

So the AC line indicator should have the needle in the red area of the meter,
this is a measurement of the AC heater voltage (which will be the same for each mains voltage tapping and thus indicate correct AC mains voltage whatever
voltage the unit is set to.)

Regarding the Guestbook for my Meazzi site some people find it works for them, others not it may be browser related..

The Magnetic Echoes Board is mine, and has not been sending me messages to say there are new topics posted on the board, so now I'm checking it
regularly for new messages. I send out a Private message to all users explaining this earlier this week..

Amanda Hambidge M0DZO / G7TUA

[Marko H]

Hi Amanda

Thanks for tipping!

Yes, General Control Meter AC line is taken direct to Pre amp Heater line. My Meazzi neadle indicate in red area (about 320)
Also Final A position neadle rise to green area. I have read to EL84 datasheet that typical operation voltage to anode is 250V.
French brochure say that green area indicates wear tubes or some other problem.
This Google translator could be better

zone verte du cadran. sert pour contröler le courant des lampes finales des amplificateurs a et b et permet par consequent de situer les lampes eventuellement epuisees ou defectueuses.

http://www.cricrimusic.fr/vieux%20catal ... meazzi.htm

Regards
Marko H
Finland

[Amanda]

Hi Marko,

The line "zone verte du cadran. sert pour contröler le courant des lampes finales des amplificateurs a et b et permet par consequent de situer les lampes eventuellement epuisees ou defectueuses."

Translates to 'green area of the dial. used to control the current final lamps amplifiers a and b and therefore allows to place the lamps eventually exhausted or defective.'

Which to me means The green area of the dial indicates the correct being drawn by the output valves and allows worn out or defective valves to be replaced if it is above or below
the green area.

When I'm back next week, I'll try and work out the diagram for the meter switching..

Regards

Amanda