## Schematics Content:

#### 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

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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,

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tube s

vin pair

The amplifier section employs two 635

Volume

2. Range tch.........5 position; Phono, AM, F2-I

5. ....... ..............,...Treble - Bass

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