Massive computer-grade filter capacitors store over 20 joules of energy. Rough appearance with questionable adhesion Fig. Determine the correct connection from Fig. The difference between success and failure in service repair is often determined by the thermal characteristics of an iron and how well it matches the job at hand. The reference designations correspond to those shown in schematic diagrams in the Review Section. Overall, Im kinda frustrated. DO NOT use excessive heat; heatsink adjacent components to prevent damage.

Q2 leaky or open 3. When this voltage reaches a positive. This wire is placed on the lead s of the component to be removed with the iron placed on top of the braided wire. Q, Q leaky or shorted 3. Just use the DA-II instead. Remove board electronics cover paragraph A, Step 2. Since transient overload can happen rapidly, a pulse stretching circuit is added so the eye can detect the LED lighting. R1 16 in the base circuit of this transistor serves two purposes:

Greater thanDCHz into 16 ohms. Rough appearance with questionable adhesion Fig. High-voltage resistance probe 1. For Bridged Mono operation: Controlled slewing-rate voltage amplifiers protect overall aeries against RF burnouts. A jumper and a resistor. Remove hardware securing transformer TI to the chassis: If not, you may wish to experiment with them in order to help improve your efficiency. Remove transformer cover and transformer schemafic around paragraph A, Step 3.

Independent level controls are mounted on the front panel. Therefore, a brief review of the following discussion on soldering techniques may be in order. If they are the “A” series, then they should have the mono switch. Miscellaneous Assembly Fig. Short, mismatch, and open circuit proof. Electrical and electronic parts on these illustrations are also identified by the circuit reference designation next to the illustration. A mono-stereo switch is located next to the input jacks on the rear panel.


To help prevent oxidation or remove existing oxidation while soldering, a natural rosin flux core solder should be used. HOdB below rated output. DC millivolt meter is connected to amplifier output. Blue ShadowJan 24, Power switch with associated pilot light is on front panel. Full text of ” Crown: Replacement of Thermal Switch, SW-1 1.


Input – ‘A seriez phone jacks, output – color coded binding posts, AC line – 3-wire grounded male connector on 5 foot minimum cable. Q, Q open, leaky or shorted 5. Remove front panel, paragraph A, Step 2. Place new transformer Tl in position on the chassis and replace, in reverse order, all item removed in Step 5.

Solder one end of brown coil wire to the output binding post terminal 55 and the other end to crpwn adjacent driver transistor terminal. Likewise, the proper size iron and tip should be used when soldering delicate electronic parts in position. Several methods are available, the most common being the braided bare copper method. Correct diameter wire tinned prior to insertion, wire used.

Crown D-150A series II Service Manual

Remove two screws 42 from top of control plate assembly. Output Assembly Index No.

Remove defective transformer Tl The early brushed aluminum preamp, the sating finished Da and the later satin Da with the IOC.

Poor assembly operation, too large diameter Remedy: Use Channel 1 input on the Crown amplifier to connect the output from your pre-amp one channel and control the output level of your power amp with Channel 1 input attenuator control knob on the front of each amp. Use wire strippers similar to the one shown in Fig. D, D, D, D shorted 2. Components leads should be bent frown exact spacing of mounting holes in PC board Fig.


Replace transformer cover and serids wrap- around paragraph A, Step 3.

Disconnect four Faston connectors from terminals of bridge DM-1 Less sschematic 15 milliohms in series with less than 3 microhenries. Removal of Control Plate Assembly 1.

How to use 2 Crown D150a amps??

Into 8 ohms, 28Vrms 98 watts should be obtainable, before signal clip. D, D leaky or shorted Negative half of Signal missing 1.

One or more strands of wire outside terminal. Should there be any question pertaining to these changes or updates, call or write the Crown Technical Service Department.

The IC op amp will always try to keep a zero potential difference between both inputs. Unsolder and tag for identification all wires and component leads connected to transistor terminals. Defective IC op amp UA 1. The A has a certain look, but I’ve seen them look exactly like schematc non-A and I think the production change-over might not have been black and white.

Therefore, it is impractical to compare soldering irons by their wattage but more feasible to refer to them by their maximum tip temperature. Schenatic of Filter Capacitors, C2 and C3 1. For this reason, at any time the covers are removed vrown is necessary to discharge these large capacitors in order to avoid possible damage to the unit and also to prevent shock hazard.