Harold Shevers, Inc. 8121 Schematic

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Product Information:
Model:8121
Manufacturer:Harold Shevers, Inc.
Description:gotham

Schematics Content:

Please note: this content is a computer-generated interpretation of the above schematic and is provided only to help assist you in locating this schematic. For the actual text, please consult the schematic above. Thank you.

Page 1:

SI-IEVERS PAGE 18-1
HAROLD SHEVE'?S, INC. MODEL 8121, (Gotham)
Fell u V -'\/gt/-I' & $3 33 Egg; , 559%/jYj>|
m.a ` ` ~--1 l EUR 3?E?= ?,?f'f?? |
(C)John F. Rider

Page 3:

12 Eva
speaker
connected
may
be used as an
volt
ring
RATIO DETECTOR ALIGNMENT
0
0
new
0
0
mum
Clio
H ave
electrolytic condenser.
M. Remove the meter leads and disconnect the 680 ohm resistor. Con- "'
nect two 100,000 ohms (il%) resistors in_series, across the 22,000 ohms E
ratio detector load resistor. Connect the common lead of the indicating
meter to the center point of the 100,000 ohm resistors and the D.C. probe '
to terminal "A" of the ratio detector transformer, T6,
5. Repeat connections as in step 2 above and adjust T6, bottom core
for zero D.C. balance. This point is approached rapidly and continued ad-
justment causes the indicated polarity to reverse. A slow approach to zero 3
is an indication of severe detuning. Q
Adjust T6 top core for minimum audio output. Alternate the ad- Q
justments of the top and bottom core of T6 until minimum audio output and Q
zero D.C. balance occur at the same point. S
6. Disconnect the two l00,000 ohm resistors and repeat steps two and J"
three, eliminating the 680 ohm resistor. 2;
(C)John F. Rider

Page 4:

_MSQPSO xmmg MOM HMOO mggwpgm wgm pOpwHMMOwO
Ng wgm mgypmgmvm wgm _OE O& LCM HGHU OMUmp Qgm gOpmp(R)Q(R)w win p(R)m _Q
MQEEHLD (R)gg(R)pQ(R) _Z_& wiv USN M(R)EEH%p OWEmg(R)O _OWO _z_m (R)?p pmsnmq _M
_L(R)p(R)E (R)np GO PBQMDO xN(R)Q MOM Wh(R)EpOMmg?gp _@_H Ggv pm5m@< _m
|w(R)Q (R)?p Op %(R)p(R)E (R)UCNpmMm(R)L Emwg QCP MO QDOLQ _O_Q min POGQQOO _H
LOHMHHHOWO "FQ :SH MOOL= USN _Ox O00 PM PG" QSM hOn(R)L(R)C(R)w (R)?p p(R)m _Q
_DSQDSO xw(R)Q POM P(R)E M%p QOOH mga UGG
LDEEWLQ POpmHHHOmO (R)?p pwghww USN "Ox OOJH Op Hwww Owgwk NSD ELSE _M
_Ox OOJH Op %OpM%(R)Q(R)w (R)?p 0259 'WEE CON
_p5mp5O xM(R)Q MOM mL(R)E%OMmQmL@ _&_H _z_< (R)?p Dm5m(R)< _@
MO (C)g(R) %OQ(R)5w(R)MM ;OH (R)?p pw pEHOQ DQHSU M Op HGHU OHUML DLQ ELSE _N
(C)John F. Rider

Page 5:

HAROLD SHEVERSQ INC. MODEL 8121, (Gotham)
A MODEL 8121 TUNER MEASUREMENTS, VOLTAGE AND RESISTANCE
Tube Pin Voltage Resistance
5 175 over 500 K
6 80 over 500 K
5 170 over 500 K
6 120 over 500 K
7 .5 U7 ohm
Ratio Detector 1 Gnd. Gnd.
Magic Eye 1 AC O
6U5/6G5 2 50 over 500 K
200 Over 500 K
5 190 over 500 K
FM driver 1 O 0
5 185 over 500 K
6 155 over 500 K
Detector 1 Gnd. Gnd.
6 100 Over 500 K
(C)John F. Rider

Page 6:

MOISEI. 8121 (Gotham) HAROLD SHEVERS, INC.
MODEL B121 AMPLIFIER MEASUREMENTS, VOLTAGE AND RESISTANCE
Tube Pin Voltgge Resistance
Input 6J5 1 Gn . Gnd.
105 over 500 K
8 11.6 1170 ohm
185 over S00 K
200 over 500 K
8 15V 220 ohm
Rectifier 5011 1 N.0. N.0.
2 360 over 1 meg
4 380 AC 70 ohm
6 380 AC 70 ohm
Inverter 6J5 1 Gnd. Gnd.
105 over 500 K
8 11.6 1170 ohm
185 over SOO K
200 over 500 K
3 15V 200 Ohm
A11 voltage taken with a 20,000 ohm per volt meter
and teken_with respect to chassis ground.
NOTE: 5 volts AC measured from pins 2 and 6 of
SUM tube.
(C)John F Rider

Page 7:

SHEVERS PAGE 18 7
HAROLD SHEVERS, INC,
0
0
0
0
tube s
vin pair
The amplifier section employs two 635
Volume
2. Range tch.........5 position; Phono, AM, F2-I
5. ....... ..............,...Treble - Bass
0
0
0
0
0
0
Ill
0

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